NSW has reported 11 more locally acquired cases of COVID-19, lifting the number of people infected in the so-called Bondi cluster to 36.

The number of locally acquired COVID-19 cases in NSW linked to the Bondi cluster has grown to 36, after 11 new infections were announced.

NSW Health figures show there were 18 new cases in the 24 hours to 8pm last night, 13 of which were announced earlier on Wednesday.

There were another six cases detected after the 8pm cut off which will be included in Friday official tally.

This means there's a total of 11 new cases reported on Thursday linked to the outbreak that began in Bondi last week.

Of the 18 cases, eight are linked to a birthday party in the Sydney suburb of West Hoxton, which was attended by a previously reported case linked to the Bondi cluster.

Sydney's COVID-19 crisis has now hit the NSW Parliament, after Agriculture Minister Adam Marshall tested positive to the virus.

Parliament staffers have been told to stay home. MPs inside the Macquarie Street building are undergoing rapid COVID tests.

Government Whip Adam Crouch has instructed MPs to "stay put" until they receive an update.

"If you are currently in Parliament House remain in Parliament House," he said,.

"If you are not in Parliament House, remain where you are," he said in a statement.

Media and non-essential staff have been told to leave, and get tested.

Mr Marshall contracted the virus after dining at Christo's Pizza in Paddington on Monday night with Nationals colleagues Trevor Khan, Steph Cooke and Ben Franklin.

The four MPs were in parliament on Tuesday afternoon after attending a partyroom meeting earlier in the day.

"This morning just after 8am I was formally advised by NSW Health that I had returned a positive test for COVID-19," Mr Marshall said on Thursday.

"I have been in isolation in Sydney since late Tuesday night, when I received a text message from NSW Health."

Mr Marshall is isolating at his Sydney flat in Sydney won't be able to return to his Armidale home for at least fourteen days. His ministerial staff are also in isolation.

Two of the three MPs who dined with Mr Marshall - Steph Cooke and Ben Franklin - have returned negative tests. AAP understands Trevor Khan also tested negative.

Ms Cooke, the member for Cootamundra, said she was "following the advice of NSW Health by staying in isolation and will be taking further tests in coming days".

Mr Franklin posted on social media late Wednesday he would get "tested again on 28 June and 3 July before coming out of isolation on 6 July".

Just 16 MPs are inside the NSW Parliament on Thursday - just enough to pass the 2021/22 budget handed down this week before the current session is suspended.

Meanwhile, Health Minister Brad Hazzard is self isolating after being exposed to a potential case at parliament.

Mr Hazzard admitted it "was likely" other MPs could be affected , noting he stands next to Premier Gladys Berejiklian every day.

Opposition Leader Chris Minns has postponed his budget reply speech due on Thursday.

"All sides agree now is not the time for politics ... we need to get through what is a very difficult health situation in Sydney," he told Sydney radio 2GB.

Mr Hazzard on Thursday played down fears Sydney is on the brink of a lockdown.

"I don't believe that we will go into a lockdown," he told ABC radio.

However, Ms Berejiklian warned on Wednesday "the NSW government will not hesitate to go further and harder if we have to".

Meanwhile, school holiday plans are in tatters for many Sydney parents under new travel restrictions.

People living or working in the City of Sydney, Waverley, Randwick, Canada Bay, Inner West, Bayside, and Woollahra local government areas cannot move outside the metro zone unless it's absolutely essential.