WASHINGTON (AFP) - As nearly three-quarters of US firms suffer supply disruptions due to the coronavirus epidemic, President Donald Trump's administration is "working full time" on a stimulus package to aid the economy.

Treasury Secretary Steven Mnuchin said Trump is "very much focused" on the package that could include a payroll tax cut, among other options.

"That's the president's number one priority," he said.

The outbreak has prompted US airlines to cancel flights, the Federal Reserve to make its first emergency rate cut in 12 years and the stock exchange to experience its worst session since 2008.

This spells trouble for the US economy but also threatens Trump's re-election campaign, which is based heavily on his touting of booming stock prices and low unemployment.

Trump promised to announce measures on Tuesday, including a cut in the taxes automatically taken out of Americans' paychecks, but the day ended with no details, leaving the United States lagging governments of other major economies.

The European Union, Italy and Britain already announced massive spending packages to provide economic support to offset the damage done by the epidemic, and even Germany, long Europe's custodian of fiscal rectitude, says it is open to more spending.

Mnuchin, who was at the US Capitol for meetings with House Speaker Nancy Pelosi and Senate Majority Leader Mitch McConnell, acknowledged that "certain industries are going to be significantly impacted and the president is very committed to make sure we have the economic response appropriately for this economy." "This is something we're going to do quickly."

Shortly after he spoke, the Institute for Supply Management released a survey showing nearly 75 per cent of US manufacturing and services firms report supply chain disruptions, and 80 per cent believe they will experience some impact from the Covid-19 outbreak.

Travel restrictions, especially from China, are a major factor, and one in six of the companies reporting problems have lowered their revenue targets, according to the survey conducted on Feb 22 to March 5.

"The story the data tells is that companies are faced with a lengthy recovery to normal operations in the wake of the virus outbreak," ISM Chief Executive Thomas W. Derry said in a statement.

"For a majority of US businesses, lead times have doubled, and that shortage is compounded by the shortage of air and ocean freight options to move product to the United States - even if they can get orders filled."

Mnuchin said he will meet with cruise line executives later Wednesday and Trump will meet with bank CEOs to discuss how they can help businesses.