There were 74,926 tests undertaken in the 24-hours until 8pm on Wednesday.
NSW Health says there are 191 people with COVID in hospital and 31 of them are in ICU.
Some 92.1 per cent of people 16 and older are fully vaccinated while and 94.4 per cent have had one jab.
Most teenagers - 81.1 per cent - aged 12-15 have had their first jab, while 75.9 per cent of them are fully vaccinated.
The hostel lockdown comes as thousands of celebrating school leavers are due to arrive in Byron Bay and other parts of northern NSW over the next month from this weekend.
Ballina MP Tamara Smith posted on Facebook on Wednesday night about the situation at the Aquarius Backpackers.
"I'm closely monitoring a situation in Byron Bay this evening where a positive COVID-19 case and 84 close contacts have been identified at Aquarius Backpackers in Byron Bay," she said.
NSW Health has locked down the hostel for seven days, impacting 84 guests.
"I'm told (they are) being supported with food, health and support," Ms Smith said.
NSW Police have placed a 24-hour guard on the hostel to ensure compliance.
"My thoughts are with everyone in that situation as it will be a tough time," Ms Smith said.
Thousands of HSC students are about to descend on the resort town for schoolies celebrations.
Some 80.9 per cent of residents in the Byron Bay local government area are fully vaccinated. Although high, the coverage rate lags the state average.
Meanwhile, unvaccinated year 12 students have been granted an exemption to attend school year 12 formals, dinners, or graduations.
Health Minister Brad Hazzard said the 2021 cohort "had an incredibly tough 18 months".
"They deserve to be able to party with their friends and enjoy one of the biggest celebrations of their life," he said on Thursday.
The exemption means year 12 students who have not been vaccinated for COVID-19 will be able to celebrate with their friends if they abide by the public health requirements of the venue they're attending.
Meanwhile, the NSW government's COVID-19 cabinet sub-committee will meet on Thursday to consider if a mask mandate will be extended beyond December 15.
The government's roadmap out of lockdown says restrictions will ease when NSW reaches 95 per cent double vaccination or on December 15 - whichever comes first.
That's when the lockout of unvaccinated people will end and masks will only be required on public transport, planes and airports and for indoor front-of-house hospitality staff.
However, there are reports NSW Health bureaucrats are pushing to keep masks mandatory in shops during the entire festive season.