"The risk is extremely low - very, very, very low - because she (the traveller) is right at the end of her potential infectious period", Queensland's Chief Health Officer Jeannette Young told media.

There are now 20 active cases in the state, while 19,000 tests were undertaken in the last 24 hours following the positive result to UK's highly contagious strain which came from a woman who worked as a cleaner at Brisbane's Hotel Grand Chancellor quarantine hotel.

They are not required inside homes, restaurants or bars, or other places where people can socially-distance.

This doesn't mean there won't be more cases, but Dr Young says if any of those contacts do come down with the virus, they're in quarantine now and won't pose a danger to the wider community.

Authorities are now working on additional contact tracing, and genome testing.

"We know this particular variant of COVID-19 is more contagious, so this result is unsurprising", she said.

Police monitor entrances to the Hotel Grand Chancellor in Brisbane's CBD, used as a COVID-19 quarantine site, the day after a casual cleaner in her 20s tested positive for the virus, marking Queensland's first case of community transmission in 113 days.

She would not comment on whether one more case of community transmission of the United Kingdom variant would put the state into lockdown again.

Despite the new case, there is no change to the restrictions due to come into force in Greater Brisbane tonight.

Masks must be carried at all times and must be worn in indoor places including shopping centres and supermarkets, gyms, workplaces where people can not socially distance and where it is safe, places of worship, libraries, public transport, taxis and ride-share vehicles.

Everyone in the Greater Brisbane region will be required to wear masks until at least 1am on January 22.

Dr Young said additional testing of other close contacts of both the man and woman will continue this week.

Dr Young is still trying to find "less risky contacts" who visited three venues at the same time as the woman last week.

The man is understood to be the cleaner's partner, and had been in quarantine since January 7.

Brisbane's three-day lockdown will end at 6 p.m. on Monday night.

"This is a really important reminder".

"The reason why we have to continue to be vigilant is that globally this virus is getting worse....the World Health Organisation has reported that for the third week in a row we have seen positive cases of 4 million new cases a week and we have seen an increase of 3% in the death rate", D'Ath said.

The decision to end the lockdown comes after the state recorded no new locally acquired cases overnight.

Two of them had also been in the United Kingdom, where a new variant of the virus is swamping hospitals.

Earlier today the NT and ACT lifted the ban but the states have so far held off.

Tasmania also allowed several thousand people who had arrived from Greater Brisbane before 9am on 8 January out of quarantine on Monday.