The National Rugby League's "terrible" off-season "cannot and will not ever be repeated", says its chief executive.
Two players have been banned this week after being accused of domestic violence and sexual assault.
"Every fan has been appalled by the procession of off-field indiscretions," said Todd Greenberg.
The NRL - Australia's domestic competition - has brought in new rules meaning players accused of "serious crimes" are automatically banned.
Under previous rules, players could continue playing until the outcome of their court cases.
'The videos I have seen are gross'
St George Illawarra forward Jack de Belin, who pleaded not guilty to a sexual assault charge in February, was the first player to be banned under the new "no-fault stand down" policy on Thursday.
Manly Sea Eagles centre Dylan Walker has also been suspended after being charged for an alleged domestic violence-related assault on his fiancee.
"I would hope that the sanctions being handed down will remind clubs and players that there are significant consequences for not complying with the standards and rules we set for our game," said 48-year-old Greenberg.
"We have already put Ben Barba out of the game. The prominent player has had his registration cancelled and his privilege to play in the game withdrawn."
In February, the NRL banned Barba from the competition after footage emerged of him in an alleged "physical altercation" with his partner.
Canterbury Bulldogs forward Dylan Napa was fined 10% of his salary by the NRL on Friday after lewd videos were leaked online.
"The videos I have seen are gross, juvenile and disrespectful," said Greenberg.
"If there was a grading in our system for stupidity this behaviour would be at the very top."
The NRL is widely regarded as the world's premier domestic rugby league competition. The new season starts on 14 March.