The man in his 20s tested positive on Tuesday after 8pm and wasn’t included in official figures until Thursday.
The Byron Bay man contracted the virus after sitting near a hen’s party which was attended by two infectious women from Queensland.
The infection sparked fears the highly contagious UK strain of the virus could be spreading in the northern NSW coastal town.
Health Minister Brad Hazzard said the development meant it was too risky for a popular annual music festival to go ahead – leading NSW Health to cancel Byron Bluesfest on Wednesday afternoon.
The festival was due to begin on Thursday and expected to host up to 16,000 revellers over five-days.
Coronavirus restrictions have been imposed for Byron, Ballina, Tweed and Lismore, with gatherings limited to 30 and the “four square metre” rule reintroduced.
Masks have also been made mandatory in some settings.
Meanwhile, a snap lockdown of the greater Brisbane area will end at noon on Thursday after only one new case of community transmission was recorded in Queensland.
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NSW has been mirroring the Queensland Health restrictions for anyone in NSW who has been to Brisbane since 20 March, and those people will also no longer be required to stay at home from 1pm on Thursday, Sydney time.
Premier Gladys Berejiklian said cancelling Bluesfest and reintroducing new restrictions were disappointing but necessary actions.
“I know businesses might be disappointed, please know that they can still open,” she told the Nine Network.
“The good news is everything is still open. We’re just asking people to take those extra precautions … just until the end of Easter.”
Late on Wednesday, NSW Health issued new alerts for a gym in Lennox Head, 20 minutes south of Byron Bay, and the Suffolk Park Hotel/Motel, just 10 minutes away.
Ms Berejiklian has promised the border will remain open and anyone returning from Queensland will be welcome but may need to isolate at home for three days.
“That is why NSW has been really keen to keep our borders open so that if our citizens do go elsewhere into other states, they are always welcome back into their state.