Time to crack down on NRL contracts: Green

North Queensland coach Paul Green wants the NRL to crack down on clubs trying to induce players to make early transfers before their contracts are up.

Green remains steadfast that the Cowboys won't agree to an early release for youngster Kalyn Ponga to join Newcastle before the beginning of his 2018 deal, despite continued pressure to let him go.

Instead, the 2015 premiership-winning coach believes any suggestion Ponga should be released is unfair.

"We're under enormous pressure from different people to release Kalyn Ponga and there was no reason why we should," Green told TAB Radio on Tuesday.

"We held our end of the bargain, he'd signed for another year so that was our attitude all the way through."

Ponga's situation has become a common trend throughout the NRL in recent years.

Last year, Newcastle allowed Joseph Tapine to head to Canberra a season early after the promising back-rower was locked in for 2017.

They have also released Korbin Sims to Brisbane in the past week, after the forward wanted out of the final year of his contract to head north.

Green is sick of the insinuation that players should leave a club early once they have signed with a team for the following season.

"It's actually illegal to try and induce someone to break their contract, so it's pretty prickly territory there for all parties concerned," Green said.

"I think it's an area of the game that can be tidied up."

Newcastle have continued to publicly state they accepted the Cowboys' position on Ponga, but were ready to welcome the star fullback if he was released.

One way to solve the problem, as far as Green is concerned, is to stop players signing for a club more than a year in advance.

Green's stance comes a day after Brisbane halfback Ben Hunt signed a deal with St George Illawarra from the 2018 season.

"It leaves a sour taste in everyone's mouth and disconnects those players with their fans," Green said.