The Prime Minister has been advised by Treasury that the impact of the coronavirus pandemic could be worse than the impact of the 2008 global financial crisis (GFC).

"The preliminary advice I have received from the Treasury this weekend is that the economic impact of the virus on New Zealand could be greater than the impact of the global financial crisis," Jacinda Ardern said on Monday.

The Prime Minister says based on the advice, because the GFC led to a recession, Treasury is now predicting a COVID-19 recession too.

The Government is announcing its massive economic support package on Tuesday so Kiwis will learn more about the consequences and the response from Finance Minister Grant Robertson.

The Prime Minister has also announced that any gatherings of over 500 people are now banned in New Zealand indefinitely.

Smaller gatherings can still go ahead for now, but the Government is working on a separate plan to manage events like weddings and funerals.