Australia's second-most populous state, Victoria, has made masks mandatory along with a number of new restrictions after recording its highest number of daily coronavirus cases.
It comes after the state recorded 723 cases of coronavirus and 13 deaths, the highest numbers since the beginning of the outbreak in the state.
Mouth and nose covering will now be obligatory in the state of more than six million people.
Victoria state Premier Dan Andrews said that in certain local areas, businesses would stay open but people would no longer be able to visit friends and family.
"Understandably, there’ll be plenty of questions about why this and not that. Why you can have dinner together at a restaurant – but not at a mate’s place. And the simple truth is, the data. The data is telling us that outside work, this is the single greatest cause of transmission in these communities," Andrews said in a statement.
"People are visiting friends and family – and taking the virus home with them."
Prime Minister Scott Morrison said the main concern is that at least 50 cases have no known origins.
"I mean, in New South Wales there are no known cases with no known source... s that is the heart of the concern about where this goes from here," Morrison said, talking about boosting testing and contact tracing capabilities.
People went to work with symptoms
Australia was seen as an early coronavirus success story but is now seeing a resurgence of cases, particularly in Victoria. Some are also being seen in New South Wales, the country's most populous state. The border between the two states is closed.
Melbourne, the capital of Victoria state, is currently about halfway through a six-week lockdown that could be extended.
Victoria Premier Andrews said last week that the cause of the spread could be attributed to people going to work with symptoms.
"Of the 3,810 Victorians who tested positive for coronavirus over the past three weeks, almost 90 per cent kept going about their business after they began to show symptoms," Andrews tweeted last week.
"It's about recognising that far too many people are either not taking this seriously enough – or they're having to make an impossible choice."
Andrews implored people to stay at home if they feel sick to curb the virus' spread.
Back in March, Victoria state recorded fewer than 100 cases per day but since early July, it has been recording hundreds.
Many European countries are also alerting the public over a slight resurgence in coronavirus cases amid fears surrounding a second wave of the virus.