NSW has recorded its first case of coronavirus in more than 50 days.
The health department said on Sunday a quarantine hotel worker tested positive after working at two different Sydney hotels which host returned travellers.
"The source of the new infection reported overnight is under investigation and urgent genome sequencing is underway," NSW Health said.
"Testing of close contacts of the case is also urgently underway."
It is the first case of community transmission in NSW in 55 days.
It comes after Queensland confirmed a case of Covid-19 in a doctor treating patients at Brisbane's Princess Alexandra Hospital.
Health authorities are treating the doctor as if she has the highly contagious UK strain although this is yet to be confirmed.
Queensland also recorded a new case on Sunday but health authorities do not believe it is connected to the PA Hospital doctor.
NSW Health Dr Stephen Conaty said on Sunday anyone who arrived in the state from Queensland after March 11 to check Queensland Health's advice.
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