Gold Coast have been fined A$300,000 ($330,000) and hit with a suspended penalty of four competition points over a salary cap breach in regard to former playmaker Scott Prince.
Prince left the Titans at the end of 2012 and the penalty was issued after an investigation by the NRL integrity unit which was instigated by the new management of the club.
Four other clubs - Manly, Newcastle, Sydney Roosters and the Wests Tigers - have been issued with fines of more than A$90,000 for less serious cap breaches.
The Titans have had A$75,000 of their fine and the docking of the competition points suspended because they self reported to the NRL.
The NRL yesterday said Prince was paid substantially more than the contract lodged with the NRL by a previous Titans board.
"This difference in remuneration was never disclosed by the previous Titans administration or Mr Prince and was only unearthed by the new management."
However, the NRL said there was no evidence of systematic rorting of the salary cap at the Titans.
The suspended fine and points will be applied if there are any further salary cap breaches by the Titans over the next two years.
In a separate investigation into the Brisbane Broncos, the NRL said they had found no evidence of a salary cap breach.
The four other clubs were hit with varying fines due to breaches in 2013.
Manly were hit with a A$6000 fine for an overspend breach, the Knights A$35,519 for the same offence, the Roosters were slugged for A$40,000, with A$20,000 suspended for two years, with the penalty due to "a lack of substantive notes of negotiation".
The Tigers were fined A$9326 for an overspend on the youth competition.
Despite the penalties, NRL general manager of integrity Nick Weeks was satisfied clubs are playing by the rules.
"I am satisfied that clubs are generally attempting to meet their salary cap duties," he said. "But all clubs are on notice that we have drawn a line in the sand.
"If clubs breach the salary cap in the future they will face heavy penalties, including the loss of competition points."
-AAP