Health authorities in NSW have confirmed 40 new coronavirus infections, bringing the state's total to 307.

Key points: About 20 government agencies will be based at the new coronavirus headquarters

About 20 government agencies will be based at the new coronavirus headquarters It will be based at the Rural Fire Service building in Western Sydney

It will be based at the Rural Fire Service building in Western Sydney The NSW Premier also backed the PM's calls for people to stop stockpiling food

While the total number of cases continues to rise, the number of new infections actually decreased from the previous day, when 57 were recorded.

Of the 307 cases, 129 were acquired overseas and 59 were contacts of confirmed cases.

Six people are in intensive care units.

NSW Premier Gladys Berejiklian said about 20 agencies dealing with the response to COVID-19 outbreak in the state would now be based at the NSW Rural Fire Service (RFS) headquarters at Lidcombe in Sydney's west.

"It's been a big operation moving 20-odd agencies and different parts of government into the one headquarters, but an important and vital step," Ms Berejiklian said.

The new hub will bring together police, health, education and transport services, amongst others, from around the state.

The Premier has also flagged an overlap between the pandemic and the bushfire season and said the RFS was putting in new contingency plans.

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Ms Berejiklian said she was pleased to see people following health advice and practicing social distancing.

"All of us have to assume we have [the virus]. You have to act in a way as though you have it and [think] how you won't transfer that to other people," Ms Berejiklian said.

"We don't want to see an escalation in the number of people who need intensive care in hospitals.

"That's our aim, to keep that number down, and we can do that by reducing the spread and especially protecting the most vulnerable and all of us have a role to play."

The Premier repeated Prime Minister Scott Morrison's message on Wednesday that stockpiling of goods which has left supermarket shelves bare was "un-Australian".

"Please stop that activity, it's not necessary, it's not needed," she said.

"Please be a good neighbour [and] be a good citizen. Do not panic buy."

Ms Berejiklian also said the State Government was calling on councils to lift restrictions on late-night stock deliveries to supermarkets.

"If some of us have to put up with trucks delivering goods in the middle of the night, so be it."

NSW's Chief Medical Officer Dr Kerry Chant said most patients with COVID-19 were being managed at home and only those with more serious symptoms would be admitted to hospital.

She acknowledged health authorities were moving away from the early precautionary approach of admitting all cases to hospital.

Dr Chant said the latest cases meant those who attended an event at the Sydney University Football Ground from 7.30pm on March 14 must now self-isolate for 14 days.

She said the health department was working to contact all those who attended the function between the University of Sydney and the University of Queensland rugby clubs.

"It [was] clearly a large function ... so we do urge everyone to take public health advice seriously and please self-isolate," she said.