Residents in NSW and Victoria have been told to check exposure sites after two new cases emerged last night.
Victoria Health tweeted on Sunday night a hotel quarantine worker had tested positive for COVID-19 after returning a negative test.
"The individual is being interviewed and a full public health response is underway, the tweet said
"We are contacting Holiday Inn Airport workers and others who are considered primary close contacts. They are required to immediately isolate, get tested and remain isolated for 14 days."
Earlier that day NSW Health said a returned traveller had tested positive two days after they were released from managed isolation.
The person had tested negative twice during the 14-day stay and NSW Health said it was carrying out a public health follow up after several venues were potentially exposed to the virus.
“Test results indicate that the person has a low level of infection and their household contacts have returned negative results to date,” NSW Health said in a statement on Sunday night.
Five positive cases in New Zealand have been linked to the Pulman Hotel in Auckland, with returnees testing positive for COVID-19 after completing MIQ.
Since late January, everyone who has completed managed isolation at the Pullman has been required to self-isolate at home for a further five days and be re-tested.