NSW has recorded an additional locally acquired case of Covid-19 a day after a community case was identified in Sydney's east.
The latest infection is the wife of the original case, a man in his 50s. Both cases are included in Thursday's numbers.
Premier Gladys Berejiklian confirmed to reporters on Thursday the original source of the infection has been identified after health authorities were initially puzzled over how he had acquired the virus.
Chief Health Officer Dr Kerry Chant said genomic testing linked the latest cases with a returned traveller from the US at a Darling Harbour quarantine facility. However, there is a missing link between the traveller and the two cases, she revealed.
"We are obviously concerned there is an intermediary," she said.
Health authorities have identified more than a dozen exposure sites which are spread widely across Sydney.
Ms Berejiklian announced certain restrictions in Greater Sydney would be tightened until Sunday.
People are now only allowed to welcome 20 people into their homes, she said.
Masks will be compulsory at supermarkets, indoor events and on transport.
Patrons inside bars must sit down while drinking.
The changes will begin at 5pm on Thursday.
Health Minister Brad Hazzard stressed the importance of people using QR codes wherever they go.
He said contact tracers had experienced a "terrible night" as they attempted to piece together the virus's route into the community.
Premier criticises other states over leak responses
Ms Berejiklian took aim at other states who have implemented snap lockdowns in response to the emergence of cases in the community.
“Unlike other premiers, we're not shutting down the city. We're not changing the two square metre rule. Quite the contrary. We're saying to everybody business as usual but just do a few things extra to make sure that until we identify those cases,” she said.
“It’s a very proportionate response.”
She said restaurants and hospitality venues should remain open as usual as long as they are adherent to Covid plans.
Any Mother's Day plans at venues will go ahead, she added.
"It's business as usual."
Queensland Health Minister Yvette D'Ath announced on Thursday anyone who has visited the Sydney exposure sites must quarantine for two weeks from 1am Friday.
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