Frydenberg said the economic shock was now expected to be "deeper, wider and longer" than was believed just 10 days ago and additional measures would be required.
The country appears poised to slip into recession as a result of the coronavirus outbreak after a record 29-year run of economic growth.
Australia has recorded more than 1,300 cases and seven deaths from COVID-19.
Prime Minister Scott Morrison said the government was also "moving immediately" to recommend against non-essential travel, warning further measures were imminent to deal with localised outbreaks.
He said work-related trips, the transport of essential supplies and travel on compassionate grounds could continue but people should cancel any other travel plans ahead of the upcoming Easter school holidays.
"More stronger measures will be coming and they will be coming in more localised areas to deal with outbreaks," Morrison said.
"What that means is, what may be necessary in a part of Sydney may not be necessary at all in... other parts of the country."
Australia has already sealed off its borders, putting in place an unprecedented ban on entry for non-residents in the hope of stemming the rise of COVID-19 infections.
Four Australian regions -- the island state of Tasmania, South Australia state, Western Australia state and the Northern Territory -- have also implemented a 14-day self-isolation period for all visitors.
Announcing the state's border closure Sunday, Western Australia Premier Mark McGowan said he was considering using Rottnest Island -- a popular tourist destination and former Aboriginal prison site -- as a quarantine zone for people who refuse to self-isolate or are unable to do so.
New South Wales and Victoria states on Sunday announced a shutdown of non-essential services, with supermarkets, pharmacies and petrol stations among those businesses that are exempt.
Morrison said political leaders would meet Sunday evening to consider stricter isolation rules.
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