Ms Pavey has been tested and will remain in lockdown until she receives her result and further advice. The orders followed news that Northern Tablelands MP Adam Marshall tested positive for COVID.

The Agriculture Minister has been in isolation since he was notified by health authorities of a possible exposure after he dined at a Sydney pizza restaurant on Monday night.

He confirmed the news on Thursday morning after getting his test results. He was notified just after 8am. He was tested twice on Wednesday.

All MPs working in NSW Parliament in Sydney this week were directed to have an immediate test and wait in self-isolation, many of them in their offices, until results were returned.

Ms Pavey has been in Sydney since Monday for the delivery of the 2021 Budget.

She confirmed she was present at a Nationals' Budget dinner on Tuesday night, where Mr Marshall attended.

Ms Pavey said she will now be guided by the expert opinion of NSW Health.

"We all have a role to play to contain this virus," Ms Pavey said.

The NSW Premier, Gladys Berejiklian, was also tested and returned a negative result. The Premier has been cleared as a casual contact of Mr Marshall.

The news is expected to have major ramifications for NSW Parliament. Already the opposition's Budget reply speech has been cancelled while some parliament staff have been told not to enter parliament.

Meanwhile, NSW Health Minister Brad Hazzard has played down fears Sydney is poised to go into lockdown after revealing he is self-isolating after being exposed to a person who could have COVID-19.

Mr Hazzard received a text from NSW Health overnight informing him he has been in close contact with a likely coronavirus case.

He was exposed at NSW Parliament House but was not experiencing any symptoms, he told ABC TV on Thursday.

Mr Hazzard admitted it "was likely" other MPs could be affected.

Premier Gladys Berejiklian has warned "the NSW government will not hesitate to go further and harder if we have to".

As of Thursday's figures, the NSW coronavirus cluster has blown out to 36 infections.

New rules are in place for residents in Greater Sydney, the Central Coast, Blue Mountains, Wollongong and Shellharbour on Wednesday.

A household guest limit of five, including children, and the four-square-metre rule indoors and outdoors were introduced alongside mandatory masks in all indoor non-residential settings, including workplaces.

Other states have hardened their borders days before NSW public schools break for two weeks.

NSW Health administered 17,976 COVID-19 vaccines in the 24 hours to 8pm June 23.

The total number of vaccines administered in NSW is now 1,993,638, with 729,783 doses administered by NSW Health to 8pm June 23 and 1,263,855 administered by the GP network and other providers to 11.59pm June 22.

There are more than 300 COVID-19 testing locations across NSW, many of which are open seven days a week.