The Rugby League Players Association has welcomed the possibility of an NRL transfer window but wants proof of its viability before giving it the tick of approval.

The governing body on Wednesday revealed it was looking into shaking up its player market system with the introduction of up to two transfer periods as early as the 2020 season.

A working group will be set up to sort out the details of the concept, which could lead to NRL clubs confirming player signings only during allocated windows.

However in what may be seen as a restriction of trade, the mooted change may also limit players’ ability to negotiate deals at any time through the final year of their contract.

It could also pave the way for the likes of rival codes to swoop in for uncontracted talent.

RLPA boss Ian Prendergast said the union had proven its openness to accepting changes to the collective bargaining agreement on numerous occasions.

And while he insists the league is now one of the most balanced competitions in the world, he said the association went to great lengths to agree to the current player-market set-up.

“The free labour market is something that past players and the Association have fought hard to establish,” Prendergast said.

“Together with the salary cap, it has served the game well in terms of providing players with a fundamental right to choose their employer and helping balance talent relatively evenly across the competition.

“Any changes to the player movement system would need to be evidence-based and consider the intended and unintended consequences of how they would work in practice, while ensuring the rights of players, key stakeholders and the competition are protected.”

While NRL boss Todd Greenberg admitted the finer details had yet to be mapped out, he hoped to introduce the changes by the start of the 2020 season.