US virus cases mount, rush to aid economy

New York is shutting schools, places of worship in New Rochelle that's seen a spike in virus cases

As US coronavirus cases have risen steadily, the White House and Congress has negotiated measures to bolster the US economy and Americans' pay cheques against the outbreak's impact, although there is no immediate sign of a deal.

The rise in the number of US cases of COVID-19, a highly contagious and sometimes fatal respiratory illness, has concerned health officials and spurred calls within Congress for action to expand testing and avert an economic meltdown.

"We had a good reception on Capitol Hill. We're going to be working with Republican and Democratic leadership to move a legislative package," Vice-President Mike Pence, who is leading the White House's coronavirus task force, told a White House briefing.

Almost three-quarters of US states have confirmed cases of COVID-19. A Johns Hopkins University tally puts the number of cases at 1025, with 28 deaths.

Washington state's governor warned of tens of thousands more cases without "real action" and New York's governor deployed National Guard troops as a containment measure in hard-hit New York City suburb New Rochelle.

US stocks rebounded on hopes a stimulus package was in the making. However, on Wednesday, Asian shares and Wall Street futures fell as growing scepticism about Washington's stimulus knocked the steam out of the rally.

A central feature of the administration's proposal is payroll tax relief, although the extent and duration of the proposal are unclear.

White House officials have also said the administration could undertake executive action to help small businesses and workers, including those who do not receive paid sick leave.

Trump is scheduled to meet bank executives at the White House on Wednesday.

US Treasury Secretary Steven Mnuchin, who is leading negotiations on behalf of Republican President Donald Trump, met Democratic House Speaker Nancy Pelosi to discuss a possible deal.

Pelosi warned any package should not contain "trickle-down solutions that only help a few".

Trump met Republican lawmakers and again played down the risks from the coronavirus. "It will go away. Just stay calm. It will go away," he said.

Some Senate Republicans said a potential deal could include $US300 billion ($A461 billion) in payroll tax relief that could help people make rent and mortgage payments, or pay medical bills if family members' work hours are reduced during the outbreak.

At least 35 US states and the District of Columbia have reported infections of COVID-19. New Jersey on Tuesday reported its first death.

The United Nations said it would close its headquarters in New York to the public until further notice.

As the outbreak spreads, daily life in the United States has been increasingly disrupted, with concerts and conferences cancelled and universities telling students to stay home and take classes online.

Democratic presidential contenders Joe Biden and Bernie Sanders cancelled rallies in Ohio on Tuesday night, citing warnings from public health officials, as six states voted in the party's nominating contests.