The Queensland government is shutting down a quarantine hotel after six people staying on the same floor contracted the UK variant of coronanvirus.
Premier Annastacia Palaszcuk says all six cases in the COVID-19 cluster, who are in isolation, were on the seventh floor of Brisbane's Grand Chancellor Hotel at different times during quarantine.
All 129 people quarantining at the hotel will now be moved to another hotel and tested, while 226 people have worked at the hotel since December 30 will be isolated and tested.
Another 250 guests who have left the hotel since 30 December will be contacted and told to isolate while they're tested.
"What we are dealing with here is something that we've never had to deal with before," Ms Palaszczuk told reporters on Wednesday.
"This is a new highly infectious strain. We do not want to see this getting out into the community and that's why we have taken these precautionary steps today in the interests of the public safety."
Chief Health Officer Jeannette Young said authorities still hadn't worked out how a cleaner at the hotel initially contracted the virus from a man in quarantine who had returned from the UK.
The woman's later movements in Brisbane triggered a three-day lockdown of the entire city and outlying areas on the weekend.
Dr Young said all defence force, police and maritime safety staff who were posted at the hotel were being contacted, including those who may have left Australia.
"We've immediately worked through the night to sort all that and have that process start first thing this morning, so it's in place," she said.
"So we need to just find all those people and test them."
The total number of active cases in Queensland is 26.
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