Lake Illawarra Police first confirmed on Sunday afternoon that an investigation was underway after being called to a residence at Shellharbour on Saturday night following reports of a social gathering in defiance of lockdown orders.

After initially confirming four non-residents were moved on from the premises, further investigations saw a total of 13 people issued PINs for breaches of COVID lockdown measures that stipulate people must stay at home outside of essential activities and are not to visit other residences unless there is a reasonable excuse to do so.

Wollongong and Shellharbour remain subject to government stay-at-home orders as part of the lockdown measures applied to Greater Sydney until at least July 9, in response to the Bondi COVID cluster. In a statement released late Sunday afternoon, police confirmed 13 people were hit with $1000 fines.

"About 9.40pm (Saturday 3 July 2021), officers from Lake Illawarra Police District attended a Shellharbour home, following reports of visitors at the home," the statement read.

"Police spoke to the residents, a 30-year-old man and a 29-year-old woman. Four men - aged 21, 30, and two aged 24 - were also spoken to and it was determined they were not residents. They were all given directions to leave and return to their homes.

"Following inquiries, police have since spoken to a further seven men - aged 26, 28, two aged 30 and three aged 25 - who had also attended the home. The 11 visitors were unable to provide a valid reason for being away from home and they ,along with the two homeowners, will be receiving $1000 PINS for breaching the Public Health Order."

The gathering was an obvious breach of public health orders and also a breach of the NRL's level-four biosecurity protocols, stipulating players only leave their homes for training and other essential activities. They're also forbidden from hosting visitors.

The NRL integrity unit is investigating and its final call on sanctions could have huge on-field ramifications should a host of players be stood down or forced into 14-day isolation, with that possibility likely to hinge on whether people outside the Dragons bubble attended the gathering.

The Dragons top-grade squad were given the weekend off following their win over the Warriors on Friday, with a bye in round 17 giving them a fortnight between games. It's understood the club's Origin contingent of skipper Ben Hunt, Andrew McCullough and Tariq Sims did not attend.

It's another COVID black eye for the game after Sharks centre Josh Dugan was last week hit with a $25,000 fine and two weeks out of the game for attending a Sydney restaurant after the NRL's bubble was put in place.

Canterbury were also fined $50,000 after five players attended a Bondi pub. The quintet were sent into isolation and missed their side's 66-0 drubbing at the hands of Manly on Saturday.

Vaughan was sanctioned over a biosecurity breach last season, fined $10,000 and forced into isolation after it was revealed he went for breakfast at a Wollongong restaurant in breach of protocols.

"St George Illawarra are aware of a New South Wales state government stay-at-home order and NRL biosecurity breach involving a number of players," the club said in a statement.

"The Dragons will not make comment at this time, while the investigation into the matter with the NRL Integrity Unit and NSW Police continues."