United States senators and Trump administration officials have reached an agreement on a significant economic stimulus bill to alleviate the economic effect of the coronavirus pandemic, White House official Eric Ueland has said.

"We have a deal," Ueland told reporters on Wednesday, after days of negotiations on the package, expected to be worth $2 trillion.

The Senate's Republican majority leader, Mitch McConnell, was expected to speak on the Senate floor shortly about the agreement.

The text of the pact was not expected to be available until later on Wednesday.

The package had been expected to include a $500bn fund to help hard-hit industries and a comparable amount for direct payments of up to $3,000 to millions of US families, as well as $350bn for small-business loans, $250bn for expanded unemployment aid and $75bn for hospitals.

It aims to cushion the economic blow from a pandemic that has killed more than 660 people in the US and sickened more than 50,000, shuttered thousands of businesses, thrown millions out of work and led states to order 100 million people - nearly a third of the population - to stay at home.

The money at stake in the stimulus legislation exceeds what the US government spends on national defence, scientific research, highway construction and other discretionary programmes.