Wayne Bennett says the NRL could not have done more to stamp out match fixing.
In the wake of allegations that two games involving Manly in 2015 are being investigated by NSW police, Bennett believed match fixing would be a potential problem for any sport as long as greed existed.
There have been calls for the NRL to be given access to players' bank and phone records to ensure the governing body has greater control.
They came after it emerged Manly's round 16 match against South Sydney and their round 24 clash with Parramatta last year were the subject of a preliminary NSW Organised Crime Squad investigation.
The NRL will reportedly lobby to strengthen its ability to investigate gambling-related issues in upcoming negotiations over a new collective bargaining agreement that will come into force next year.
In the meantime, NRL boss Todd Greenberg said anyone found guilty of match fixing faced a lifetime ban.
"What I like about us is that we are proactive with it," Bennett said.
"Everyone knows if you get caught the penalties are going to be huge.
"We can't do any more than that."
Bennett said tennis match fixing allegations that emerged in the New Year showed it could emerge as a problem in any sport.
A sweeping integrity review was ordered by tennis' top bodies in January after reports emerged ahead of the Australian Open linking top-ranked players to corruption in the sport.
"Every sport has the same battles," Bennett said.
"No one was more surprised than me when tennis hit the headlines.
"I thought that would be a sport where it didn't happen.
"It's all about temptation and greed ... right across the game and society."
Bennett said the problem would not go away especially with betting agencies so easily accessible.
"Our big challenge - and I don't know the answer to it - is mobile phones," he said.
"You don't have to go to the TAB any more.
"Now you can lose a hell of a lot of money on your phones."