One of the teenagers accused of bringing COVID-19 back to Queensland after a trip to Melbourne is refusing to tell authorities about her movements in the days since she returned home.

The woman is one of two 19-year-olds confirmed to have the deadly virus but skipping quarantine after returning to Brisbane.

The pair and another friend returned from Melbourne via Sydney on July 21.

The friend has so far tested negative for the virus. But the infected pair spent eight days in the community before their infections were confirmed this week.

• Queensland shuts its borders after teenagers bring in COVID

Queensland police say the women picked up the virus at a party in Melbourne. All three women are now in quarantine.

They have reportedly been fined $4000 each for making false border declarations. A criminal investigation has been launched into how they bypassed mandatory quarantine.

The 22-year-old sister of one has also been confirmed with the virus – the state’s first community transmission of COVID-19 in two months.

Queensland chief health officer Dr Jeannette Young said one of the young women was refusing to cooperate with authorities.

“The second confirmed case has not wanted to let us know where she has been,” she said.

“That is why I am spreading that message that if anyone is unwell, to please get tested because I don’t know where that second case has been.”

A dental practice, five restaurants and bars in six suburbs, including Southbank, South Brisbane, Woodridge, Browns Plains and Sunnybank, were all exposed to the virus by the women in the days before they teted positive.

Shopping centres, restaurants, a school and a church have been closed.

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Deputy Commissioner Steve Gollschewski said Queensland Police would take the women to court.

“They knowingly and deliberately deceived us,” he said.

“One of the first two women has been cooperative, the other has not. We are still working with the third person.

“We know these three young women have all gone to Victoria, where they have been exposed to COVID. They will all go towards the court, and charges will be formalised today.”

Queensland confirmed three more coronavirus infections on Thursday. They are in a returned overseas traveller and in a couple who dined at the Apollo restaurant in the Sydney suburb of Potts Point, where several COVID cases have been confirmed. The couple have been self-quarantined at home for several days.

“Over the last two days, we have had six new cases,” Dr Young said.

“It has been a long time in Queensland since we have really had those sorts of new case numbers. So this is an increasingly risky time.”

Queensland’s state has stepped up coronavirus testing, especially in Brisbane’s south, since the women’s positive cases emerged this week. There were lengthy queues at fever clinics on Wednesday and Thursday.

Queensland police say they have issued well more than 1100 infringement notices since COVID border measures were introduced, and 40 people had made false declarations.