An impassioned US President Barack Obama Friday cranked up pressure on Republicans to back his new tax cuts, deploying the fireworks of the campaign trail to promote his new economic plan.

Obama traveled to the key 2012 swing state of Virginia, the political turf of one of his top Republican foes Eric Cantor, at the start of an effort to sell his $447 billion American Jobs Act in every corner of the country.

The president dared his foes in Congress not to support his plans to cut in half payroll taxes for workers next year, exploiting the traditional Republican desire to reduce the money Americans pay to the government.

"You guys have made pledges never to raise taxes on everybody, ever again. You can't make an exception when the tax breaks are going to middle class people," Obama said, addressing his "good Republican friends."

The president also renewed his call on Republicans to permit tax increases on the richest Americans and to close tax loopholes for oil firms and other corporations, setting up a new battle in Congress.

And before a raucous crowd in an indoor sports arena which at times recalled the electricity of his 2008 campaign, he pleaded with supporters to email, call, tweet and even send a "carrier pigeon" to lawmakers to support him.

He welcomed the measured response of some top Republicans to his plan delivered in the House of Representatives on Thursday night, as both sides of the political aisle feel heat from voters frustrated over the economy.

"To their credit, I was glad to hear some Republicans, including your congressmen ... (say) they see room for us to work together. They say they are open to some of the proposals to create jobs," he said.

"I know folk sometimes think they have used up the benefit of the doubt, but I am an eternal optimist," Obama said, expressing hope the plan could pass despite the skepticism of many political observers.

Cantor, who heads the Republican majority in the House and has been one of Obama's most strident critics, was due to hold his own jobs event in Virginia later on Friday.

And in a post on Twitter, he laid out the response of Republicans who want the president to slash regulations on small businesses.

"I welcome the President to Richmond. I hope he hears the same message I do back home, it is time for Washington to get out of the way."

Despite saying the election was 14 months away and calling on Republicans to ditch political partisanship, Obama made a highly political speech himself, as he seeks to rebuild public trust in his economic leadership.

"If you want construction workers on the worksite, pass this bill!" Obama roared, drawing cheers from a crowd estimated to be about 9,000 strong and packed with young voters who were a vital part of his 2008 coalition.

"If you want teachers in the classrooms, pass this bill! You want a tax break, pass this bill!"

Bolstering the political theme, Obama pointed with a smile at a man to his left in the audience who was holding a makeshift sign reading "4 more years".

On Thursday, in a high stakes speech to a joint session of Congress that may represent his last chance to turn around the economy before the 2012 election hits top gear, Obama called on Republicans to halt the "political circus."

He said the plan, weighted towards tax cuts but also containing investments in creaking US infrastructure, would "provide a jolt to an economy that has stalled."

The centerpiece of the proposal is a deeper-than-expected $240 billion payroll tax cut for employers and employees meant to keep money in the pockets of those most in need, spur demand and encourage firms to hire new workers.

Some key economists on Friday gave him a mostly positive review, despite the fact the plan is highly unlikely to emerge unscathed from the Republican-led House of Representatives.

Mark Zandi at Moody's Analytics said : "President Obama's jobs proposal would help stabilize confidence and keep the US from sliding back into recession."

Zandi estimated the plan would add 2.0 percentage points to GDP growth next year, add 1.9 million jobs, and cut the unemployment rate by a percentage point.

But US stocks fell sharply on opening, with investors questioning whether a weakened Obama can convince Congress to pass the plan.