Almost 12 million Australians are now subject to stay-at-home restrictions after Victoria announced another snap lockdown.

The lockdown is the state's fifth and comes in response to a growing coronavirus outbreak.

Travel restrictions are in place, with gatherings capped at two people and no visitors allowed to homes.

There are only five reasons to leave the house including essential shopping and getting vaccinated.

More than 100 exposure sites have been listed across Victoria, which has recorded 36 active cases.

There are fears the statewide closure could stretch beyond five days if case numbers explode.

Sydney residents face at least another two weeks of restrictions with NSW in the grips of a major outbreak.

The state recorded 97 local cases on Friday, most of which were detected in Sydney's southwest, with 75 people admitted to hospital and 18 in intensive care.

NSW Premier Gladys Berejiklian is bracing for a further spike in case numbers, given at least 29 of the latest cases were infectious while in the community.

"This is the concerning number. That number of people being infectious in the community keeps going up," she told reporters in Sydney.

"We really want to stress to everybody, please stay at home, follow the orders."

With the country's two major cities in lockdown, the federal government is overhauling business and individual assistance for the third time in six weeks.

Prime Minister Scott Morrison said the changes would simplify and streamline the assistance package.

He has agreed to fund immediate support payments for Victorians forced out of work.

People who have lost at least 20 hours of work will get $600 while those who have lost between eight and 20 will receive $375.

No liquid asset tests will be applied.

National cabinet will meet on Friday afternoon to discuss the vaccine rollout and support payments.

Mr Morrison wants state and territory leaders to agree to a new method of supporting individuals and businesses suffering financial loss, with more lockdowns expected this year.

Labor deputy leader Richard Marles said the Morrison government was struggling to keep up with lockdowns.

"The real point here is they are making it up as they go along and that is creating an enormous amount of uncertainty," he told ABC radio.

Earlier this week, the official vaccine advice was updated for Sydney residents in coronavirus outbreak zones.

Older residents were encouraged to bring forward their second doses of AstraZeneca, while people aged under 40 were advised to consider the vaccine if Pfizer was unavailable.

Health Minister Greg Hunt has not recommended the same approach for under 40s living in Melbourne.

"When it opens for them - and the advice we have is September, October will be the period - then we'd encourage every Australian to come forward and be vaccinated," Mr Hunt told 3AW radio.

"If we have an opportunity to do it earlier, obviously we will."

Australian Associated Press