Washington (AFP)

President Joe Biden will on Wednesday propose a $2 trillion infrastructure plan aimed at modernizing the United States' crumbling transport network, creating millions of jobs and enabling the country to "out-compete" China.

The first phase of Biden's "Build Back Better" program, which he will unveil in a speech in Pittsburgh, will detail massive investment spread over eight years.

It plans to inject $620 billion into transport, including upgrading 20,000 miles (32,000 kilometers) of roads and highways, repairing thousands of bridges and doubling federal funding for public transit.

The president, whom Donald Trump tried to caricature as "Sleepy Joe" and a man without strong ideas or motivation, intends to make the bold infrastructure plan one of his flagship policies.

"He views his role as laying out... a broad vision, a bold vision for how we can invest in America, American workers, our communities," White House spokeswoman Jen Psaki said.

The investment would be partly paid for by raising corporate tax from 21 percent to 28 percent.

"The President is proposing to fundamentally reform the corporate tax code so that it incentivizes job creation and investment... and ensures that large corporations are paying their fair share," a senior administration official said ahead of the speech.

The new legislative offensive comes soon after Congress passed a nearly $2 trillion Covid-19 economic stimulus plan.

And Biden's speech is set to open a bitter battle in Congress, where the Democrats hold only a narrow majority and will face strong opposition from the Republicans.

The coming months will test the negotiating skills of the Democratic president, a veteran of Washington politics and deal-making, to the limit, and the chances of his infrastructure plan passing into law remain uncertain.

- 'Urgency of the moment' -

"It's an important initiative to start the process with the president being very clear that he's got a plan, and that he's open to hearing what others think," the administration official said.

"But what he is uncompromising about is the urgency of the moment and the need to really deliver for the American people and make good on building back better in this moment."

The plan also vows to "spark the electric vehicle revolution" by building a network of 500,000 EV chargers, replacing 50,000 diesel transit vehicles and electrifying 20 percent of the famous yellow school buses.

And it aims to make infrastructure more resilient to climate change.

With much of the country's creaking infrastructure dating back to the 1950s, the dream of new roads, bridges, railways and airports is shared by many Americans.

But building a political consensus to transform Biden's plan into reality is no easy task.

Both his predecessors Barack Obama and Trump had great ambitions and made heady promises over infrastructure investment, but struggled to make any progress.

The issue keeps coming back to the same question: how to pay for it?

Biden's new transportation secretary Pete Buttigieg, who ran against him in the Democratic primaries, will be on the front lines of the battle, trying to ensure that this time, the stars are all aligned.

"I think that there's a tremendous opportunity now to have bipartisan support for a big, bold vision on infrastructure," the youthful politician said.

"Americans don't need a lot of selling to know that we've got to do big things when it comes to our infrastructure."