Premier Daniel Andrews has cast doubt on today's much-anticipated easing of restrictions as health authorities scramble to contain an outbreak in Melbourne's northern suburbs.

The state has fallen below 100 active cases for the first time in four months, however, struggling businesses could be disappointed if the premier follows through on a warning to postpone a substantial COVID restriction roll back.

Six new infections have been linked to a growing cluster resulting in isolation orders for hundreds of people and an asymptomatic testing blitz.

It's a potential drawback for struggling business owners who were holding out for the announcement.