NSW Agriculture Minister Adam Marshall has tested positive for COVID-19 after he and three other MPs dined at a Sydney pizza restaurant that was later identified as an exposure site.
Parliament House employees were told on Thursday to stay home and journalists and non-essential staff were told to leave the building while MPs underwent rapid testing.
Government whip Adam Crouch urged politicians to "stay put" while they await an update on the evolving situation.
"If you are currently in Parliament House remain in Parliament house, if you are not in Parliament House, remain where you are," he said in a statement.
Mr Marshall revealed he had received a positive test on Thursday morning shortly after NSW Health Minister Brad Hazzard, who has since tested negative, announced he was isolating after being notified he could be a close contact of a possible COVID-19 case.
The Nationals MP told Radio 2GB he was asymptomatic and had been in full isolation since Tuesday night, the same day the NSW budget was handed down.
Mr Marshall and three Nationals colleagues attended Christo's Pizza in Paddington on Monday night, where a positive case linked to the Bondi cluster also dined.
"To everyone who has contacted me this morning, thank you for your thoughts and well wishes - I’m doing fine and will continue to strictly follow the advice of health authorities," Mr Marshall said in a statement.
NSW Health Minister Brad Hazzard is in isolation after coming into contact with a possible positive COVID-19 case. Source: AAP
The Armidale resident is isolating in his Sydney flat, while his ministerial staff have also been forced into isolation. At least two of his colleagues who visited the restaurant - Steph Cooke and Ben Franklin - have confirmed they've returned negative tests.
Earlier on Thursday, Mr Hazzard told the ABC he had received a text from NSW Health overnight notifying him he may have been in contact with a likely positive case at NSW Parliament House.
"I'm talking about somebody who works for NSW Parliament who may be a positive case," he said.
Hours later he released a statement that he had returned a negative test result and had his status changed to casual contact, meaning he is able to stop isolating.
Premier Gladys Berejiklian told journalists she has also been deemed a casual contact after isolating and returning a negative test on Thursday morning.
"Colleagues are going through that process this morning to ensure that nobody enters the chamber to pass the budget until all of those assessments have been made," she said.
A , bringing the total number of infections linked to the Bondi cluster to 36.
But Mr Hazzard attempted to quell fears that a lockdown was set to be imposed, stating: "I don't believe that we will go into lockdown".
"I think we actually need to take health advice and the health advice is that the new orders that came into play yesterday afternoon are proportionate to our risk."
Opposition Leader Chris Minns told 2GB it was "not the time for politics" and has postponed his budget reply speech.
"We need to get through what is a very difficult health situation in Sydney," he said.
A range of new public health measures came into force on Wednesday afternoon, including a restriction on people who have been in seven local government areas - City of Sydney, Waverley, Randwick, Canada Bay, Inner West, Bayside, or Woollahra - from travelling outside metropolitan Sydney.
Residents of Greater Sydney, the Central Coast, Blue Mountains, Wollongong and Shellharbour are also subject to a five-person at home visitor limit and compulsory face mask rules in all non-residential indoor settings.
