Guests at an Auckland managed isolation facility allegedly mingled with apartment block tenants - during a fire alarm.

An AUT student with Covid-19 lives at the Vincent Residences, which is right next door to the Grand Millennium.

The hotel was evacuated on Monday evening - but there's reports no barriers were in place to separate returnees and the public.

But Auckland University Covid-19 Modeller Shaun Hendy told Chris Lynch the student was already unwell by then.

"That event probably wasn't it. If there was a similar event or there has been mingling, particular with staff then that's a concern, as we know from time to time, staff members are becoming infected."

He says the lack of a link makes this case more worrying than other recent cases. 

"The risk is we're looking at the tip of an iceberg, and that this is actually the first case we might have detected in a much larger cluster of infections." 

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