The declaration was due to expire on Thursday.

This means that Police Commissioner Darren Hine will remain in control of border controls.

Premier Gutwein said he would confirm the state's position on borders following a national cabinet meeting on Friday morning.

He has previously indicated that borders could be open to other states on July 24 - except for Victoria.

A declaration of a state of emergency gives Mr Hine, as state controller, far-reaching powers under the Emergency Management Act.

In his role, he liaises with Public Health director Mark Veitch to co-ordinate the government's response to the coronavirus pandemic.

It gives him authority to take resources from different government departments.

Under law, a state of emergency cannot exceed 12 weeks in relation to a disease in humans or animals though the Premier is able to extend the declaration if there are reasonable grounds to do so.

The declaration can be revoked at any time.

A step down from a state of emergency is a state of alert which can be declared over seven days.

This also gives the state controller broad powers under the Emergency Management Act.

Labor leader Rebecca White said the decision to extend the state of emergency declaration was the right thing to do amid unprecedented circumstances in Victoria.

But she said that more clarity was needed in regards to essential workers following Wednesday's announcement of tougher border restrictions with the neighbouring state.

"Peter Gutwein has finally indicated that quarantine exemptions already granted for essential workers will be reviewed, but Labor would like more detail on the scope of that review," she said.

"It is a serious oversight that we currently have people who have been granted essential worker status moving around the community without having to be tested for the virus."