There were 27 new cases overnight, taking the total number since the outbreak began to 900 on Saturday morning.

On Friday there had been 39 new cases and 57 on Thursday.

Across the state, medical workers have carried out 56,000 tests for COVID-19 since the crisis began. Four Queenslanders have died and 56 people remain in hospital. Eight are in intensive care wards, with six requiring ventilators.

Health Minister Steven Miles says there has been a stabilisation in the number of people being diagnosed with the virus.

"Usually in an outbreak, if you did not put measures in place you would see an exponential rate of growth," he told reporters.

"We are not seeing that ... and that is very, very welcome."

Mr Miles said the majority of new cases continued to be from Australian returning from overseas.

"We have virtually no community transmission," he said.

He said a week ago the number of new cases was doubling every three to four days but that had now slowed and it was now taking nine to 10 days to occur.

"Every other country in the world would love to have Australia's health system (and) would love to have the results we are seeing," he said.

Mr Miles said Queensland had now flattened the curve but remained in the early stages of the outbreak.

About 15 to 20 per cent of people who contract the virus will continue to need hospitalisation. The job ahead is to find, isolate and contain the virus in a bid to limit its spread until a vaccine becomes available, he said.

Meanwhile, photos of a popular Brisbane Saturday morning farmers' market show customers gathering in large numbers.

Mr Miles said it was concerning and it was up to shoppers and stallholders to follow the rules otherwise the operation would be reviewed.

Asked how long the state's social distancing regulations will remain in place following the fall in new cases, Mr Miles said people should expect to remain at home for at least a month.

However, he said some of the measures may continue for more than six months.

Australian Associated Press