Acting Premier Steven Miles said Queenslanders with travel plans to the area might consider waiting out the 24 hours to see if the cluster gets worse.
He said Chief Health Officer Jeannette Young will make a call by Friday about whether to name geographic hotspots but hopes it won't come to that.
"It could well be the case that we have just these five cases, that they can be linked, they can be isolated, and that there are no other cases," he said.
Miles expressed his confidence in New South Wales' (NSW) health system in handling outbreaks, including quarantine, response, and contact tracing.
"We hope and are sure that they will get on top of this very very quickly," he said. "But this is early days, this is new information, and so over the next 24 hours we will be monitoring it very very closely."
Four locally-acquired COVID-19 cases have been reported on the city's northern beaches since Tuesday.
Queensland only fully opened the state border to greater Sydney earlier this month after it had been closed since August.
The acting premier stressed that a hotspot approach would be much more likely than a complete border closure, which would require a more widespread virus outbreak in the neighbouring state.