Premier Daniel Andrews on Sunday announced a suite of tough new COVID-19 regulations designed to limit movement in Melbourne, while foreshadowing more to come for workplaces.

Under “stage four” rules to run until at least September 13, metro Melbourne has been placed on a nightly 8pm-5am curfew starting from Sunday night.

The rare health-related restriction was prompted by the state recording 671 new cases on Sunday – it’s second-highest daily total – and seven further deaths. It is understood Victoria has recorded an additional 429 cases in the past 24 hours.

Treasurer Josh Frydenberg has declared Victoria is “at war” as the Federal Government weighs up extra economic support to guide the state through its supercharged lockdown.

Extending eligibility for JobKeeper wage subsidies and introducing paid pandemic leave are being considered after the state spent its first night under curfew.

Frydenberg said JobKeeper in its current form would continue until the end of September, which is later than lockdown is slated to last.

“We are at war. Every Victorian is on the front line. Everyone has a role to play,” he told the ABC on Monday.

“We can’t afford any holes in our defences.”

The Treasurer noted some major employers had already introduced pandemic leave, while the state government also provides support for people needing to isolate.

Industrial Relations Minister Christian Porter is consulting with unions and business groups to see if more needs to be done.

Victoria is in a state of disaster with tough new restrictions as coronavirus infections and deaths continue to surge.

Premier Daniel Andrews is expected to announce further measures curtailing business activity on Monday.

Frydenberg said the impact on Australia’s economy would be greater than the $3.3 billion Treasury estimated the initial six-week lockdown would cost.

“Victoria is a quarter of the national economy,” he said.

“This is a real kick in the guts to Victorian businesses, which will have an impact on employment.”

The state recorded a further 671 cases on Sunday, with seven more deaths taking the national toll to 208.

Under the new measures, one person from every household will be allowed to shop once a day.

Exercise will be limited to one hour a day and like shopping, must be within five kilometres of households.

Police, who have been armed with extraordinary state of disaster powers, will enforce a curfew between 8pm and 5am during the six-week lockdown.

Meanwhile, the NSW government is strongly recommending people wear masks in high-risk situations.

Public-facing workers, worshippers, people living near community clusters and those in enclosed spaces, such as on public transport or in grocery shops, should wear face masks.

NSW recorded 13 new virus infections overnight.

Melbourne residents will also only be allowed to exercise for an hour a day and can’t travel more than 5km from home for shopping or exercise.

Only one person per household can shop for groceries each day, while recreational sports such as tennis and golf have been banned altogether.

With a state of disaster declared, police have additional powers to fine anyone caught breaking curfew or outside a 5km radius of their home without reasonable excuse.

Victoria’s Premier flagged further announcements on employment rules on Monday, including the closure of some workplaces in certain industries.

“There will be significant changes to a number of workplaces in terms of how much they’re doing,” Andrews told reporters.

But he assured Victorians supermarkets, grocery stores and bottle-os would remain open in a bid to discourage a fresh wave of panic-buying.

Meanwhile, regional Victoria has moved to “stage three” restrictions, with restaurants, cafes, bars and gyms to shut from midnight Wednesday.

While acknowledging the drastic moves were necessary, the Victorian Chamber of Commerce said they would undoubtedly mean the end for many businesses.

Peak tourism body, Victoria Tourism Industry Council, said the restrictions would further devastate the state’s ailing tourism and event industry.

Mitchell Shire, to Melbourne’s north, has been reclassified as a regional municipality meaning it will remain under ‘stage three’ rules.

Victoria’s latest deaths take the national toll to 208, with six of the seven connected to the age care sector.

Seventy-three of the new cases are linked to known outbreaks, 598 remain under investigation and 760 “mystery cases” are yet to be traced to an original source.

-AAP, additional reporting by ABC