Mitchell and Addo-Carr both apologised for a weekend gathering at a property near Taree, with Mitchell admitting the Kangaroos stars had "slipped up".

The NRL's integrity unit will also continue its investigations, as police revealed Addo-Carr had also previously been warned for breaking the Public Health Act.

Photos posted by Addo-Carr showed the pair with 10 other men around a fire, prompting the NRL to label the pictures as disappointing and unacceptable.

He was also seen shooting a gun and riding a dirt bike without a helmet, while NRL-contracted Newcastle fringe player Tyronne Roberts-Davis is seen in one of the photos.

"Police have been told a group of more than 10 men were at a gathering on a rural property near Taree on Saturday 25 April, in contravention of current ministerial directions," NSW Police said in a statement.

"Following extensive inquiries, three men - two aged 22 and one aged 24 - have been issued with $1000 (fines) for failing to comply with a ministerial direction.

"The 24-year-old had previously received a warning for breaching the Public Health Act.

"Inquiries are continuing to identify the other persons and continue investigations.

"Investigations are also continuing into other potential offences, including potential breaches of the Firearms Act (1996) at the Taree property."

The fine also came on the same day the league further pushed its claim for a return, discussing its strict biosecurity rules with clubs on Monday afternoon.

But Mitchell insisted they did not mean to flout rules imposed by the federal and state governments to stem the coronavirus pandemic.

"I have been up here with my family for four or five weeks practising social distancing," Mitchell said in a video.

"It was a little bit of a slip up.

"Foxy (Addo-Carr) reached out, his cousins are going through a bit of stuff up in Sydney.

"He just wanted to get up to the bush and make sure they were getting cultured and connected again.

"That was the whole part of the concept of what the weekend was.

"I wasn't here to break any rules or hurt anyone.

"We're not being selfish, I couldn't turn down the brothers in a time of need.

"On behalf of Foxy and all my mob, we do want to apologise."

A repentant Addo-Carr said "nothing was intentional or deliberate" as he tried to "put a smile on the faces" of family members going through a tough time.

But under NSW guidelines people can only leave the house for work, essential shopping, exercise, medical appointments and compassionate visits.

All NRL players also agreed to health and safety protocols when the competition was stopped for the shutdown.

"On face value, the image in today's media is both disappointing and an unacceptable breach of health orders," the NRL said in a statement.

"The NRL will be speaking to the players involved to seek further information and we will ensure the players provide any assistance authorities require.

"Our players are role models and we expect them to lead by example during this pandemic."

The drama could not have come at a worse time for the NRL as it attempts to convince the government it can safely resume its season on May 28, ahead of other major codes.

Proposed NRL biosecurity rules for the season resumption will make players stay home - with no visitors allowed - except when training, playing, making visits to the doctor and doing essential food shopping.

The NRL has threatened teams with the loss of points and heavy fines if any player breaks the rules, and say they will further educate players before next week's planned resumption of training.

However Australia's chief medical officer Brendan Murphy said the actions of the pair would not influence any government decision.

Australian Associated Press