Two players with National Rugby League team South Sydney Rabbitohs were rushed to hospital on Tuesday after overdosing on painkillers.

Dylan Walker, 20, and Aaron Gray, 21, were admitted to an intensive care unit at Sydney's St Vincent's hospital after the pair were found in a serious condition at the latter's residence, the club said.

They were placed under heavy sedation upon their admission and their condition had improved over the course of the day, club CEO John Lee told reporters in Sydney.

“What we also know is that last night Dylan Walker... came round to (Gray’s) place where they watched some movies but also... they had taken more than the regulated amount of prescribed medication.

“The consequence of that was that early in the morning, a third person who was at the house noticed that there were side-effects, including vomiting and other side-effects, which led him to alert an ambulance.”

The players, who are life-long friends, had been prescribed painkillers following surgery last week in the wake of the team’s exit from the NRL playoffs.

Walker had undergone an operation on his left hand, while his team mate had surgery on his right knee.

Lee said the players had shown signs of waking after their sedation and expected their condition would improve further over the course of the day.

“It is very early times,” he added. “It would appear that the medicines they have taken have been overpowering for them.”

NRL chief executive David Smith said the club had notified the league's integrity unit.

“I think one (player) was quite serious overnight but they’re both stable now,” Smith told reporters.

“The key thing for me is the welfare of the players.

“Fingers crossed that all works itself through and if we need to investigate further, we’ll do that.”