The Premier of New South Wales has issued a warning to her state, telling citizens she's "absolutely convinced" there are people with COVID-19 who have no idea they're infectious.
Gladys Berejiklian's comments come as the state struggles to suppress a second wave of the disease and neighbouring Victoria's case numbers continue to explode to record highs.
New South Wales recorded 17 new coronavirus cases of COVID-19 on Monday, which is about average for daily case numbers over the last fortnight.
While there are just 160 active cases of coronavirus across the entire state - just a fraction of Victoria's 4542 - Berejiklian is wary of getting complacent.
And she told 7 News' Sunrise programme she's "absolutely convinced, as are other health experts, that there are people in New South Wales with the virus who don't know they have it."
"Whenever any of us are out and about we need to assume that we have it or that somebody else has it," she said.
"Don't assume you have the cold or the flu, assume it's the virus and act accordingly. We have to have that attitude otherwise things will get out of control."
"Our state does remain on high-alert, but we are doing okay, we're holding the line."
Queensland Premier Annastacia Palaszczuk says she "will not hesitate to slam the border shut" if New South Wales' community transmission rates climb higher.
"Let me reassure Queenslanders once again, every single day we are monitoring what is happening in New South Wales," she said on Monday.
The main point of concern for New South Wales officials is a pair of outbreaks at two restaurants of the same name, Thai Rock. A cluster formed in one of the restaurants, in the city's west, has now grown to 70 cases.
NSW Health is now investigating how this occurred, and is looking into whether there were staff that worked across both locations.
"They are under the same management structure so we're currently investigating whether there is a crossover of staff or how that could have occurred," NSW Health's Dr Kerry Chant said.