With just four rounds remaining before half the league enters its off-season, Greenberg on Wednesday warned clubs about the consequences of misbehaviour.

"I reminded the clubs today that that's the last time I'll see all 16 club CEOs in a room until well into September," Greenberg said.

"And I reminded them of their obligations as leaders of their clubs to ensure that they are well-prepared for anything that happens post-season.

"Onus of responsibility is on clubs and players.

"It's pretty simple: Behave yourself, enjoy yourself, but hold yourself to account and understand you represent the game at all times."

Greenberg's comments come as the integrity unit closes in on completing its investigation into Parramatta forward Shaun Lane.

Photos emerged this week appearing to show Lane holding a bag of white substance reportedly during end-of-season celebrations with Manly last year.

Lane went on to join the Eels over the summer, where he has become a critical part in their push from wooden spooners to finals contenders.

A punishment is expected to be handed down before the weekend, with Lane likely to be heavily fined.

Sea Eagles coach Des Hasler, who wasn't at the club last year, was reluctant to discuss the details of the events but suggested the photos may have been a joke.

"For players, it'd be idiotic to try and, particularly in regards to the image of the game, if it was a gee-up or a bad joke," Hasler told reporters on Wednesday.

"Who knows what the powder was? It could've been Panadol or Disprin.

"At the end of the day, don't risk it, because it sounds, at the end of the day, there's going to be a hefty fine on the back of it."

Hasler was unsure if eliminating Mad Monday celebrations was the solution.

"It's a discussion that's always come out ... define what Mad Monday is. There's just got to be smart planning and accountability shown."

The latest scandal comes after the game introduced a no-fault stand-down policy for players charged with serious criminal offences earlier in the year.

Greenberg said the strengthened code gave him confidence that the game would endure less drama off the field this off-season after a plethora of incidents after 2018 had wrapped up.

"We now have the strongest rules in any sport in this country, and you might argue stronger than any other rules across the world in relation to sanctions of players and the ability for us to hold players out for alleged behaviour or charges," he said.

"We've demonstrated that this year on three individual occasions.

"And I've been very clear publicly from the start of this year right to now, that if you put yourself out of the crease, you give the game a black eye, and you behave poorly, there will be consequences.

"I've been criticised this year a number of times for going hard at players for those consequences, and we're going to keep doing it because if players keep doing the wrong thing, they're going to get a whack from the game."

Australian Associated Press