Dozens of Sydney Harbour party boat passengers are being told to get tested and isolate after test results indicated two fellow revellers were infected with the Omicron variant of the coronavirus.
Late on Tuesday, NSW Health said five people on a December 3 cruise, marketed as Flow Fridays — 90s Themed Boat Party, had tested positive for COVID-19.
"Genome sequencing to confirm if any of the five confirmed cases have the Omicron variant is underway – preliminary results indicate two are likely to have it," the department said, in a statement.
"All cases are isolating at home.
"NSW Health is urgently contacting around 140 people who signed in with a QR code before boarding the boat and directing them and members of their households to immediately get tested, isolate and await further public advice."
Authorities said the cruise, operated by Cadman Cruises, left King Street Wharf 9 at 7.30pm and returned about 11pm.
On a Facebook event page set up for the cruise, organisers last week reminded guests to keep their mask on at all times unless eating or drinking and to bring proof of COVID-19 vaccination or an official exemption.
"Flow Presents and Cadman Cruises are COVID-safe businesses and abide by all current health orders and guidelines," they said.
"We kindly ask that all patrons assist us with compliance and social distancing."
A further six cases of the Omicron variant were detected in New South Wales on Tuesday, bringing the total number at that point to 31.
None have needed hospital treatment and most are linked to a cluster in Western Sydney.
Victoria is testing a sample from an overseas arrival for the new variant.