Wall Street’s main indexes have hit record highs as President Donald Trump’s signing of a long-awaited $US2.3 trillion ($A3 trillion) pandemic aid bill bolstered bets on an economic recovery and drove gains in financial and energy stocks.

In a sudden reversal late on Sunday, Trump backed down from his threat to block the hard-fought bill, restoring unemployment benefits to millions of Americans and averting a federal government shutdown.

“Trump signing the COVID relief and government spending bill has gotten uncertainty out of the way, and the market right now is on autopilot – creeping its way higher into the new year,” Sam Stovall, chief investment strategist at CFRA Research, said.

All the 11 major S&P sectors were higher, with financial, energy and industrials among the biggest gainers.

The S&P 1500 airlines index added 2.2 per cent as carriers are set to receive $15 billion in addition payroll assistance under the new government aid.

Cruise operators Royal Caribbean Cruises Ltd, Carnival Corp and Norwegian Cruise Line Holdings Ltd also rose between 3.3 per cent and 4.3 per cent.

Trading volumes are expected to be thin in the final week of the year that has historically been a seasonally strong period for equities.

After a sharp recovery from a coronavirus crash in March, the S&P 500 is on track to rise more than 15 per cent this year on the back of a loose monetary policy, high liquidity and a COVID-19 vaccine program.

At 9:51am Eastern Time, the Dow Jones Industrial Average rose 204.85 points, or 0.68 per cent, to 30,404.72, the S&P 500 gained 25.82 points, or 0.70 per cent, to 3,728.88 and the Nasdaq Composite gained 81.25 points, or 0.63 per cent, to 12,885.98.

Democrats in the US Congress on Monday will put to vote a proposal for higher pandemic-relief payments for Americans, although it appears unlikely to gain traction in the Republican-controlled Senate.

Fuelling a global appetite for risk, Britain and the European Union clinched a lean post-Brexit trade deal on Thursday, while the launch of a mass COVID-19 vaccination drive in Europe over the weekend added to the upbeat mood.

Tesla Inc rose 2 per cent after a report that the electric-car maker will start operations in India early next year.

Advancing issues outnumbered decliners by a 2.9-to-1 ratio on the NYSE and by a 2.1-to-1 ratio on the Nasdaq.

The S&P 500 posted 23 new 52-week highs and no new lows, while the Nasdaq recorded 308 new highs and nine new lows.