Coronavirus: New South Wales records 124 new cases of COVID-19, the highest of the outbreak

New South Wales has recorded 124 new cases of COVID-19 - the highest number in a single day since the outbreak began. Of those, 48 were infectious in the community.

Premier Gladys Berejiklian had a grim warning on Thursday: "Given that number of infectious in the community, I am expecting case numbers to go up even higher."

She told locals to "brace" for the higher case totals in coming days. The virus is "spreading like we have never seen before", but the Premier said the total would have been in the thousands without restrictions or the contact tracing team.

Thursday's numbers are up on 110 cases recorded on Wednesday, of which 43 were infectious in the community.

Of the locally acquired cases, 67 are linked to a known case or cluster – 45 are household contacts and 22 are close contacts – and the source of infection for 57 cases is under investigation.

NSW Health says 37 cases were in isolation throughout their infectious period and 22 cases were in isolation for part of their infectious period. Forty-eight cases were infectious in the community, and the isolation status of 17 cases remains under investigation.

There are 118 people in hospital, with 28 in intensive care.

"Unfortunately, the two main areas of transmission areas again, or the two main places where people are getting the virus or spreading the virus continue to be in workplaces and also in households," Berejiklian said.

"Unfortunately, when our health experts are interviewing families within households, we're learning that they have visited families in other households and the disease is spreading through that way but unfortunately, also in workplaces."

There was a record 85,000 tests undertaken over the last 24 hours.

Queensland Premier Annastacia Palaszczuk announced on Thursday that the state's border with NSW would close from early Friday morning to "reduce the risk of COVID-19 spread". 

"This is an important step that allows Queensland to safely ease COVID-19 restrictions across the state," she said.

Queensland didn't record any local or overseas cases on Thursday, while Victoria reported it had recorded 26 new local cases, it's highest daily figure yet this year. New Zealand currently has a pause in place on quarantine-free travel from NSW, Victoria and South Australia.