Health officials are warning a number of COVID-19 positive people linked to a Newcastle nightclub have "likely" caught the new Omicron variant.
Twenty-four people who went to a prom night-themed event at the Argyle House last Wednesday night have tested positive to COVID-19.
Three of the nightclub patrons are linked to a party boat cruise on Sydney Harbour two weekends ago, that has been the source of multiple Omicron infections.
NSW Health says "a number" of the 24 new cases have likely been caused by the new variant, and it's likely that more people will test positive to Omicron.
The Hunter New England Health District has recorded its first Omicron case, from a recently returned traveller from the UK who is confirmed to have the strain.
She's not connected to the Argyle COVID cluster, and Hunter Public Health Controller David Durrheim said the woman was safely isolating at home.
Sydney cruise links
NSW Health said a public health investigation was underway into the transmission of the virus.
Dr Durrheim said more Omicron cases were expected in the Hunter region.
"We probably should prepare that we are going to get more Omicron cases coming in from overseas with open borders," he said.
"It is very important that we don't ignore even the mildest of symptoms … fever, sore throat, a runny nose, a cough, should prompt us to again get tested."
