Newcastle has become a NSW COVID-19 hotspot after a man with the virus visited several pubs at the weekend and attended a local A-League match.
The man in his 20s is a close contact of a Newcastle teenager whose diagnosis shut down his high school on Thursday and sent two football teams into self isolation.
The man attended several venues in Newcastle between Friday and Sunday, including Bennett Hotel in Hamilton, Sydney Junction Hotel in Hamilton and the Wests leagues club in New Lambton.
NSW Health wants anyone who attended those venues between specific times to immediately self-isolate for 14 days from the day they attended, and get tested.
The man also visited the Greenroof Bar and Restaurant in Hamilton, the Queens Wharf Hotel, Sushi Revolution in Hamilton, and was among spectators at the Newcastle Jets-Western United match on Sunday at McDonald Jones Stadium.
Anyone who visited those venues on those dates is considered a casual contact and is advised to be alert for symptoms.
There were 2570 spectators at the Jets game but only the lower level of the stadium was open, with seating in the bays capped at 25 per cent to allow for social distancing.
Football Federation Australia says the match operated under the COVID Safe Plan and the stadium was undergoing a full clean.
Meanwhile, Premier Gladys Berejiklian appealed to the state's youth to modify their social life.
"We are on a knife-edge and we are about halfway through what is a really critical period," she told Triple M radio on Thursday.
"To the young people, try and modify the number of places that you go to."
St Pius X College in Newcastle announced it was closed until next week while authorities traced an infected boy's close contacts among the 1050 students and 200 staff.
The teenager last attended school on Monday when he caught the No.26 Hamilton to Adamstown school bus. Everyone on that bus is required to isolate for 14 days and seek testing.
He was also in the Jets under 15s squad that played against the Stanmore Hawks at Arlington Oval in Sydney's Dulwich Hill on Saturday.
All players in that game have been asked to isolate for 14 days and the teen's close contacts will be notified and must also isolate.
Hunter New England Local Health District said it was still investigating where the boy contracted the virus.
The teenager is among the 12 new cases reported in the 24 hours to 8pm on Wednesday.
The other cases include one linked to the Apollo Restaurant in Potts Point, one who attended the Mounties club in Mount Pritchard and eight who are household contacts of known cases.
There are now 107 cases associated with Thai Rock restaurant in Wetherill Park, 58 linked to the Crossroads Hotel cluster, 50 connected with the funeral cluster, and 32 linked to the Potts Point cluster.
Another case is a Sydney man in his 20s who dined at the Jambo Jambo African restaurant in Glebe on July 31 from 7pm to 8.30pm. Anyone who attended the restaurant at that time should self-isolate and get tested.
The man also visited several other inner-city venues between Friday and Sunday, but patrons at these places are classified as casual contacts and just need to watch for COVID-19 symptoms.
NSW Health later on Thursday confirmed a man in his 20s in Sydney's southwest has also tested positive.
The man is a close contact of a previously reported case associated with the Mounties cluster.
He attended Penrith Plaza, Master Hot Pot in Canley Vale and BBQ City Buffet in Bankstown while infectious on August 1. People who were at these venues are urged to be alert for symptoms.
Australian Associated Press