Penrith captain Isaah Yeo has pointed to last year's grand final as proof the NRL's transfer system does not need to change, pushing against a move for the June 30 deadline to be reinstated.

The issue of contracting windows remains one of the last issues to be resolved in collective bargaining agreement negotiations, with most other components sorted.

Under a proposal put forward by the NRL in December, players would not be able to sign with rival clubs until after June 30 in the final year of their contract.

That proposal offers three extra months than the NRL's initial plans for post-season deals only, but is well short of the current rule which allows for negotiations from November 1 the previous year.

The Rugby League Players Association has made clear it does not support the move and is unwilling to have it in the CBA unless shown proof it could be beneficial.

One of the NRL's chief concerns is the frustration of fans, who grow tired of watching players sign elsewhere with a year still to run with their current club.

Yeo's Panthers already have two such instances this season, with Stephen Crichton signed with Canterbury for 2024 and Spencer Leniu informing Penrith of his impending exit.

But Yeo, an RLPA delegate, claims last year's grand final between the Panthers and Parramatta showed the early signings had little negative consequence on the field.

Before last season Penrith had already lost Viliame Kikau and Apisai Koroisau for 2023, while Reed Mahoney, Isaiah Papali'i, Marata Niukore, Ray Stone and Oregon Kaufusi had agreed to leave Parramatta.

"Kiks and Api both went and had career years and won the grand final," Yeo said.

"Parra had blokes signing elsewhere and that was their big driving factor last year to make sure they had success.

"If anything, it is only going to motivate players more to go out on a high."

Penrith are also a club who like to have contracts sorted in the pre-season rather than let them be a distraction in finals.

Moving the anti-tampering deadline back to June 30 - it was scrapped in 2006 - would change that approach.

Players have long stated their main concern is about a lack of security if they suffer an injury while waiting to sign a deal with a rival club.

"Cameron McInnes (in 2021), if he doesn't sign with the Sharks before he does his knee in the off-season, all of a sudden he is cruelled," Yeo said.

"It costs him a-couple-of-hundred-thousand plus long-term security as well. That's one example out of a number. And it's a big one.

"I know some fans might not like it. But players are worried about their security long term.

"It's a no-brainer ... There is no need to change."