Macquarie Fields MP Anoulack Chanthivong has entered self-isolation after dining at the Crossroad Hotel last week.
The Crossroads Hotel was recently closed after nine Covid-19 cases were linked to the Casula pub.
NSW Health has advised anyone who visited the pub between July 3 and 10 to immediately self-isolate and get tested for the coronavirus.
A pop-up testing clinic has been established in the Crossroads Hotel car park.
Mr Chanthivong confirmed on Facebook that he dined at the venue on July 6, and has now entered self-isolation.
"I attended the Crossroads Hotel for dinner last Monday," he posted this morning.
"As soon as I became aware of the updated NSW Health advice yesterday, I was tested and am now in self-isolation.
"As an extra precaution, I have decided to close my office to the public during the self-isolation period.
"I take the safety of my family and the community very seriously and will continue to follow all public health advice.
"Keep well, stay safe and follow NSW Health advice.
"My office is still available to assist. Please call 9618 2077 or email email@example.com."
Mr Chanthivong urged anyone who had visited the venue to do the right thing.
"We must not become complacent in helping to stop the spread of Covid-19," he told the Advertiser.
"Everyone who attended the hotel has a responsibility to get tested and self-isolate for the required period.
"The health advice is very clear: even if you don't have symptoms you must still get tested then stay home and self-isolate for 14 days since you were last at the venue."
Mr Chanthivong said it was important everyone played their part to stop the spread.
"No one wants to see an increased rate of community transmission of Covid-19," he said.
"Let's all work together to keep our community as safe as possible."
Werriwa MP Anne Stanley has also enter self-isolation after dining at the venue last week.
NSW opposition leader Jodi McKay has called for more testing facilities in the region.
"We need an all-out assault on what is a deadly enemy in Sydney's south-west," she said.
"That means a major expansion of testing. The queues around the Crossroads Hotel today have been enormous.
"A single overwhelmed pop-up clinic in the car park at the site of the outbreak isn't enough.
"We know one of the biggest obstacles to increasing tests is convenience.
"That's why the NSW Government must expand the hours of this pop-up clinic, and open more pop-ups in the area."
NSW Chief Health Officer Kerry Chant said isolation was incredibly important
"Even if you get a negative test, that does not mean you are out of the woods," she said.
"A negative result does not mean you can breach self-isolation.
"While investigations are continuing, it is vital people get tested so we can try and establish the source of infection at the hotel. I encourage people to access a number of clinics at local hospitals at Campbelltown, Fairfield and Liverpool so people are tested as quickly as possible."