Damned flight crews ! Loss of billions in valuation.

Ms Berejiklian also confirmed new rules for inbound international airline crew would roll out next Tuesday.

Presently airline crew are able to self-isolate upon their arrival in NSW in either a home or accommodation.

They are not subjected to the mandatory 14-day hotel quarantine scheme.

There are between 2,000 and 3,000 airline crew arriving in NSW a week, Health Minister Brad Hazzard said.

Ms Berejiklian confirmed there would be two police-operated hotels in Sydney for airline crew "as opposed to 25 or 26 [hotels]".

She said the "lack of compliance" was the issue that caused the rules to be tightened.

"It's the breach of the guidelines... it's people, unfortunately, doing the wrong thing."

Ms Berejiklian confirmed one airline worker who was not an Australian citizen has breached their quarantine and gone out to venues.

"Unfortunately that doesn't seem to have amounted to anything and was not subject to any consideration at this stage but that is an example a few weekends ago where aircrew are supposed to isolate and chose not to."

Mr Hazzard also flagged that rules for Australian airline crews may also tighten in the coming days.

"Some of the aircrew coming in are Australians, and the international arrangements have been that home country crews can normally go to their homes," he said.

He said mandatory testing before the airline worker returns to their household was under consideration.

Dr Chant acknowledged some airline crew live in the Northern Beaches area and were currently self-isolating there but said they were "casting the net far and wide" in their investigations.

Damned US flight crews(AFR) !!!!!!!!!!!!!