A national emergency will be declared by President Donald Trump today as the coronavirus rages relentlessly in the country.

On Friday, the US coronavirus death toll hit 41 and confirmed cases surpassed 1840.

Trump reportedly plans to invoke the Stanford Act, which will open the door to more federal aid for states and municipalities.

Senate Democrats have been urging Trump to invoke the Stanford Act and other disaster declarations, which they say will free $42 billion in funding.

The emergency, which Trump is expected to declare at 3pm Washington Time, would allow the government to marshal additional resources to combat the rapidly-spreading virus.

In a much criticised move, Trump on Wednesday, without prior warning to allies, slammed a 30-day ban on flights from Europe effective from Friday midnight. Britain and Ireland are exempted.