Queensland Police are expecting further delays at the southern border while investigations continue into the arrival of a superyacht in the north.
Chief Superintendent Mark Wheeler said police and SES crews would continue to scale up resources at border checkpoints.
"We only had a very short window of time to close the borders and implement those checkpoints," he said on Thursday.
There are currently three checkpoints operating around the clock with plans to establish a fourth.
"We can't do that overnight, we can't just simply pluck police from other rosters and make this happen Immediately," he said.
Queensland Health Minister Yvette D'Ath is concerned about undetected coronavirus cases in the state after details of two positive cases came to light on Thursday.
Sewage tests at Wynnum, Bargara and Bundaberg have returned positive results for COVID-19 and people in the areas with any sign of symptoms are being asked to get tested.
One of the cases was a 20-year-old female crew member of a superyacht that came from the Maldives and is at the centre of a police investigation.
The vessel allegedly arrived in Cairns on Monday with 14 guests plus the crew on
board.
The guests have been directed into hotel quarantine while six remaining crew members stay on the vessel.
The other case was a man who has been in self-isolation since returning from Sydney's northern beaches.
Ms D'Ath says the 40-year-old tested negative after returning from the hotspot last Friday, before becoming unwell and testing positive late on Wednesday night.
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If you are experiencing cold or flu symptoms, stay home and arrange a test by calling your doctor or contact the Coronavirus Health Information Hotline on 1800 020 080.
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