A federal MP is one of thousands of people urged to self-isolate after dining at a Sydney hotel linked to more than nine coronavirus cases.

Parts of the RAAF base at Wagga Wagga are also locked down after about a dozen Australian Defence Force personnel visited the pub at the centre of the growing outbreak.

Earlier confirmed cases linked to the Crossroads Hotel in Casula, in Sydney’s outer south-west, include an 18-year-old worker and a close contact in her 50s, plus a woman in her 40s and a Victorian man in his 20s.

The latter two, who both dined at the hotel, are the latest to test positive for COVID-19.

On Sunday night Casula’s Planet Fitness gym confirmed on its Facebook page that a member had returned a positive test for coronavirus.

“The member has not been at the club since Friday 10 July, and is in quarantine,” the gym’s letter to members said, adding that staff were in self-quarantine and it was following NSW Department of Health advice.

The gym has been closed and is being disinfected.

On Monday morning, NSW chief health officer Dr Kerry Chant confirmed more cases had been linked to the hotel. She told Sydney’s 2GB radio that the additional cases would be detailed this afternoon.

She said there are links to Melbourne’s COVID outbreak.

“We do have some linkages to Melbourne but we need some further diagnostic tests,” she said.

NSW Health has broadened its advice around the outbreak in Casula, urging anyone who visited July 3-10 to self-isolate and get tested.

Dr Chant confirmed a “small number” of ADF personnel went to the Crossroads Hotel during the affected week, and had gone into self-isolation as a precaution.

“I’m advised that none of them are unwell … testing has been undertaken and I am aware none of them are positive,” she said.

Elsewhere, federal Labor MP Anne Stanley said she dined at the Crossroads last week.

In a post to Facebook, the member for Werriwa said she had been tested for coronavirus and would go into self-isolation for 14 days. Her office has been temporarily closed.

Dr Chant said earlier the original case at the hotel was unknown.

“We do not think the staff member was the source,” she said on Sunday.

She said all visitors and staff should be tested as a precaution and self-isolate for 14 days from their last visit.

“A negative result does not mean you can breach self-isolation,” she said.

On Monday, NSW government minister Stuart Ayres said he didn’t think the state’s virus outbreak was getting out of control, but the key message was that Crossroads visitors should get tested.

“I think we’re in a pretty good place at the moment, but we are at the crossroads,” Mr Ayres told Seven’s Sunrise.

“I know it’s a pun that everyone wants to use at the moment, but there’s probably never been a more symbolically named hotel than where we sit right now.

“This particular hotel is located at the juncture of the M7 and the M5, it’s a big traveller’s hotel, which is why if anyone’s been in that location it’s so important that they go and get tested immediately.”

Dr Chant said the pub outbreak highlighted the importance of businesses recording contact details for customers and the public taking the measures seriously.

-with AAP