Image caption Obama's past calls for infrastructure investment have gone unheeded in Congress

US President Barack Obama has appealed for increased private investment in infrastructure, saying it will create jobs and boost the US economy.

Mr Obama outlined his plans at Port Miami, which is undergoing a $2bn (£1.3bn) upgrade and tunnel project.

Among his proposals was $4bn in new infrastructure loans and grants.

He also repeated a call for a $10bn "infrastructure bank" to attract investment for projects that will have the greatest impact on the economy.

The Obama administration is proposing tax breaks for foreign pension funds that invest in US infrastructure, and bonds designed to attract investors in larger projects.

"There are few more important things we can do to create jobs right now and strengthen our economy over the long haul than rebuilding the infrastructure that powers our businesses and our economy," Mr Obama said in Miami.

'Work to be done'

The upgrades at Port Miami - including a tunnel under the bay designed to link a highway with the port - are being funded by taxpayers as well as private investors.

Mr Obama noted that the involvement of several jurisdictions, as well as private companies whose payments were tied to performance, meant "construction workers are on the job digging this tunnel, doing great jobs, getting good pay".

"What are we waiting for?" Mr Obama said, turning his attention to the wider US. "There's work to be done, there are workers who are ready to do it."

All of Mr Obama's proposals require Congressional action, including the "infrastructure bank", a proposal he introduced in his first term that was never acted upon.

But the turn toward private funding is driven in part by Republican opposition to increased government spending, analysts say.

Republicans have been reluctant to support additional projects since Mr Obama and the Democrats passed a $787bn stimulus plan in 2009 that included infrastructure funding.

And Republican Florida Governor Rick Scott has criticised Mr Obama for being "late to the party", arguing Florida taxpayers have had to pick up too much of the tab for the Miami and other port projects because the president was slow to support them.

In a conference call with reporters on Friday, a senior Obama administration official said the proposals would not add to the federal budget deficit, saying details would be spelled out in the president's budget, expected to be released on 10 April.

After touring the tunnel project at the port, Mr Obama said that such projects should draw support from both Republicans and his fellow Democrats, noting that both union groups and the pro-business US Chamber of Commerce agreed on the need for increased infrastructure spending.

"I know that members of Congress are happy to welcome projects like this in their districts," he said. "I know because I've seen them at the ribbon-cuttings.

"If you think it's good for your district, then it's probably good for other districts, too."