With inflation surging at its fastest pace in 40 years, President Biden has identified a new culprit that he says is helping fuel America’s skyrocketing prices: The ocean vessels that ferry containers stuffed with foreign products to America’s shores each year.

Shipping prices have soared since the pandemic, as rising demand for food, couches, electronics and other goods collided with shutdowns at factories and ports, leading to a shortage of space on ocean vessels as countries competed to get products from foreign shores to their own.

The price to transport a container from China to the West Coast of the United States costs 12 times as much as it did two years ago, while the time it takes a container to make that journey has nearly doubled. That has pushed up costs for companies that source products or parts from overseas, seeping into what consumers pay.

Mr. Biden has pledged to try to lower costs by increasing competition in the shipping industry, which is dominated by a handful of foreign-owned ocean carriers. He has cited the industry’s record profits and directed his administration to provide more support for investigations into antitrust violations and other unfair practices.

Congress is also considering legislation that would hand more power to the Federal Maritime Commission, an independent agency that polices international ocean transportation on behalf American companies and consumers.

The bill, which has bipartisan support, would authorize the commission to take action against anticompetitive behavior, require shipping companies to comply with certain service standards and regulate how they impose certain fees on their customers. Mr. Biden is pushing lawmakers to add a provision that would allow the commission and Justice Department to review applications for new alliances between companies for antitrust issues, and reject those that are not in the public interest.

The House passed its version of the bill in December; it must be reconciled with a Senate version.

But it’s unclear to what extent more government oversight and enforcement will actually bring down shipping costs, which are being driven in large part by soaring consumer demand and persistent bottlenecks. Global supply chains are still plagued by delays and disruptions, including those stemming from the Russian invasion of Ukraine and China’s broad lockdowns in Shenzhen, Shanghai and elsewhere.

“As a standard matter of economics, if you have inelastic supply and experience a surge in demand, you will see a rise in prices,” said Phil Levy, the chief economist at Flexport, a logistics company.

The effect is expected to worsen in the coming months. Shipping rates typically take 12 to 18 months to fully pass through to consumer prices, said Nicholas Sly, an economist at the Federal Reserve Bank of Kansas City.

“The goods that are being affected by shipping costs today are really the goods that consumers and American households are going to be buying many months from now, and that’s why those costs tend to show up later,” he said.

Some of the price increases from late last summer have yet to work their way through into consumers, he said, and the conflict in Ukraine is causing further disruptions.

Shipping prices have already skyrocketed so high that, for some products, they have erased companies’ profit margins.

The cost to ship a container of goods from Asia to the U.S. West Coast surged to $16,353 as of March 11, nearly triple what it was last year, according to data from Freightos, a freight booking platform.

While supply chain congestion showed some signs of easing in January and February, the Russian invasion of Ukraine has quickly worsened the situation along with lockdowns in China that have closed factories and warehouses.

Analysts at Capital Economics, in a research note on Wednesday, said that it was still possible for China to suppress coronavirus infections without causing widespread disruption to global supply chains. “But the risk that global supply chains links within China get severed is the highest that it has been in two years,” they said.

American businesses that use ocean carriers have been pushing for additional oversight of what they say is an opaque, lightly regulated industry.

One of the main complaints among importers and exporters is that ocean carriers are charging customers huge and unexpected fees for delays in picking up or returning shipping containers, which are often mired in congestion in the ports or in warehouses. American farmers, who have struggled to get their goods overseas, say that ocean liners have refused to wait in port to load outgoing cargo or skipped some congested ports entirely. As a result, some have periodically been unable to get their products out of the United States.

Eric Byer, the chief executive of the National Association of Chemical Distributors, said American companies were having trouble getting chlorine to clean swimming pools, citric acid to make soft drinks and phosphoric acid to add to fertilizer through American ports.

“It’s taking weeks upon months, and they’re getting nickelled and dimed on costs. There are a lot of fees that are being imposed on products waiting in the San Pedro Bay,” he said, referring to the body of water outside the busy California ports of Los Angeles and Long Beach.

“It’s been a lot of turmoil and challenges, a lot of unreliability,” said Patti Smith, the chief executive of DairyAmerica, which exports milk powder to foreign factories to be made into baby formula. Her company has sometimes been unable to get its products out of West Coast ports, she said, and has racked up extra warehousing costs and unexpected fines because of the delays.

While Ms. Smith said she supported the administration’s efforts to enhance oversight of the shipping industries, she wasn’t sure that would do much to bring down overall prices.

“I wouldn’t say it would necessarily lower prices. I think it might put prices more on a level playing field,” she said.

The White House insists that its efforts can drive down costs, portraying the measures Mr. Biden announced as a way to calm skyrocketing inflation, which has become a huge economic concern among voters. Consumer prices surged 7.9 percent in the year to February, a 40-year high.

The White House has pointed to rapid consolidation in the industry over the past decade as a driver of higher prices, saying that three global shipping alliances now control 80 percent of global container ship capacity, and increased shipping costs would continue to fuel inflation.

“Because of their market power, these alliances are able to cancel or change bookings and impose additional fees without notice,” the administration said in a fact sheet.

Shipping companies have protested those assertions. John Butler, the chief executive of the World Shipping Council, which represents the biggest container ship operators, including Maersk, Hapag-Lloyd and Ocean Network Express, said the White House arguments were “simply inaccurate.” The industry is not particularly concentrated by measures that antitrust authorities use, he argued, and leading into the pandemic, there was plenty of capacity and rates had been declining.

“Nothing has structurally changed,” he said. “The increased rates coming out of Covid are driven by the fact that we’ve had this massive import surge that’s continued for over 18 months, and the inland infrastructure in the U.S. simply can’t handle it.”

Mr. Butler said that the line of ships queuing to get into major U.S. ports like Los Angeles had effectively reduced the global supply of vessels.

“You’ve got the two things at once: reduced effective capacity and increased demand. When you have that situation, something has to give, and that thing is prices,” Mr. Butler said.

Some economists have echoed those arguments, saying it’s a function of supply and demand.

“I think the spike in rates that have taken place during the pandemic is mostly due to an increase in demand for imported goods combined with port slowdowns that functionally act as a reduction in the number of ships operating,” said Colin Grabow, a trade analyst at the Cato Institute.

Daniel B. Maffei, the chair of the Federal Maritime Commission, said in an interview that there was “no question” that changes in consumer demand as a result of Covid had driven a rapid increase in shipping prices. But, he added, “does that mean the carriers have to charge this much?”

The commission has never filed an antitrust case against a carrier. But Mr. Maffei noted that “conditions are absolutely, totally different now than they were two years ago. The pandemic has changed everything.”

The shipping industry denies that its alliances have led to any collusion on prices. The alliances that ocean carriers form allow them to share space, by placing some of their own cargo on a ship operated by a partner. But these agreements specify that companies can’t discuss their prices, Mr. Butler said.

“That’s just not something that happens,” he said.

But some logistics experts say that cooperation between shipping companies has ended up reducing competition and concentrating market power, indirectly giving them more free rein to dictate prices and schedules.

Caitlin Murphy, the chief executive of Global Gateway Logistics, a freight forwarder, said small businesses in particular had been harmed by shipping practices during the pandemic, including when alliances have skipped less profitable ports. Her company had been trying to ship cargo from India to New York, but some carriers were avoiding the port at New York to bypass congestion.

“It’s reducing the supply of available vessels in India, which is driving the price up,” she said. “So it’s become very difficult to move product around the world.”