The man, linked to the cluster in Berala in Sydney's west, had been on a camping trip with friends.

On their return trip - the period during which the man became infectious - the group had stopped at locations in Orange, Nyngan and Broken Hill.

They had sat indoors at Birdie Noshery & Drinking Est on Summer Street in Orange, where bathroom facilities had been used.

NSW chief health officer Dr Kerry Chant said the man's companions had tested negative, but that they would be required to isolate to 14 days since their last contact with the man who is positive, and that they must test negative again "on exit".

Hundreds of people queued for testing on Tuesday afternoon at the Big Bogan in Nyngan.

Dr Chant urged residents of Western NSw to remain vigilant and get tested at the first sign of any symptoms.

It was a message echoed by acting premier John Barilaro and health minister Brad Hazzard.

Dr Chant said anyone who visited Birdie on January 3 between 12pm and 2pm is "a close contact and must get tested and isolate for 14 days regardless of the result".

Anyone who had been at the Nyngan Riverside Tourist Park on Saturday evening was also asked to get tested, while those who visited the Nyngan BP (where the man visited on Sunday morning) have been asked to monitor for symptoms.

There were five new cases on COVID-19 in NSW on Tuesday, with one of those found in someone from overseas in hotel quarantine.

One of the local cases was a man in his 20s, who is a household contact of a case linked to the Avalon cluster.

Another case, from western Sydney, was a household contact of a previously reported case whose source remains under investigation but is likely to be linked to the Berala cluster and another was a man in his 30s from western Sydney, whose case is under investigation.

The fifth case was the 18-year-old linked to the Berala cluster who travelled into western NSW, which was flagged the previous day.

Mr Barilaro said there had been an incremental increase in the testing numbers since Sunday, with 32,667 tests across NSW in the 24 hours to 8pm on Tuesday.

"If we can remain in the 30 to 40,000 range that would be fantastic," he said.

Dr Chant said the test numbers from Tuesday were pleasing, and said it was critical that those high testing rates remain.

She said health officials were concerned that there were unrecognised strains of the virus, particularly in the Berala area.

Dr Chant asked people to pay close attention to the health advice for certain venues, as NSW Health was issuing "initial stop and stay" advice for some places, asking people to get tested and isolated.

Once more details were known about particularly venues, the health advice may change to categorise people as casual, instead of close contacts.

Minister for Health Brad Hazzard addressed the concerns about the cricket test to be held at at the SCG, after Victoria issued alerts for the Melbourne Cricket Ground.

The Victorian government announced on Wednesday that people seated in the Great Southern Stand on December 27 had possibly been exposed to COVID-19.

Mr Hazzard said two more suburbs - Wenthworthville and Belmore - have been added to the banned list - with people from these areas to receive a $1000 fine for attending the SCG.

Any person who was in the Great Southern Stand at the MCG will also receive a $1000 fine if they attend the match in Sydney.

Transport for NSW Acting Deputy Secretary for Greater Sydney Howard Collins said the transport plan would cater for 23,000 people, despite only 10,000 people being allowed to attend.

He said mask wearing and sanitising would be necessary on all public transport, with patrons asked to observe social distancing.

People are also asked to register their Opal cards to help with contact tracing at the event.

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