Canberra Raiders boss Don Furner has called on the NRL to cap third-party agreements to help remove the inequality from the game.
Furner added TPAs couldn't be completely removed from the NRL landscape because it would disadvantage the players' earning potential compared with rival codes.
The NRL said it will review TPAs in the wake of the Manly salary-cap scandal, after the Sea Eagles on Tuesday became the second club in two years to be issued with breach notices after Parramatta was sanctioned in 2016.
Both Manly and the Eels came under investigation through their use of TPAs, with the Eels going over the cap by $3 million across five seasons.
The Sea Eagles' alleged breach isn't the same magnitude as Parramatta's, but the club and two officials have been issued with show cause notices.
TPAs have become a massive bug-bear for Raiders fans, who were frustrated by other clubs' ability to continually recruit top players yet still remain under the salary cap.
That frustration was further magnified with the Raiders forced to offload back-up hooker Kurt Baptiste due to salary-cap pressure when the $9.4 million cap was set lower than anticipated earlier this year.
Furner said while the Raiders did have some TPAs, they would never be able to attract the same amount as "the big clubs in Sydney or Brisbane".
It creates an uneven playing field - going against the reason the salary cap was originally introduced.
"We were part of a review two years ago and I made my views known on certain TPA deals. Hopefully they do review it again because it's an inequality within the game," Furner told Fairfax Media.
"Cap them, because you can't have a salary cap with this thing attached on the side which is unlimited.
"The NRL have definitely tightened things up in the last two years, which is a good thing, but it's a difficult area.
"We have got some [TPAs], but we're never going to get as many as the big clubs in Sydney or Brisbane are going to get, we're just never going to. That's the inequality that needs to be looked at."
Furner felt capping TPAs was the best answer, so that players could still sign deals to wear boots, get commentating gigs or do television commercials to further enhance their incomes.
He was a fan of a points-system salary cap, which would completely take players' incomes out of the equation.
"You can't just blanket say let's get rid of them because somebody might be offered $25-30,000 deal to wear Asics boots so you don't want to restrict that earning capacity for the players," Furner said.
"It's a difficult area once you start bringing rules into it, but we do need to look at it again.
"I've been on committees that looked at different things. I was always a fan of the points system.
"That has got it's detractors, but it's transparent and it doesn't matter what the player earns. If you've gone over the amount of points you can use you can't play them.
"It needs to be thought through because you can't just ban them because we've got players with a car deal or a boot deal, or Fox Sports, that sort of stuff."
The Raiders have currently filled 27 spots on their 30-man roster, but have several players, including forward Bill Cullen currently on train-and-trial contracts and hoping to fill those final spots.
Furner said they might even keep one spot free going into the season to allow them to fill any injuries that might arise.
"We've got a couple of spots, we're not rushing so we'll see," he said.
"You just don't know what's around the corner, what injuries you might get so I think it's prudent to leave a spot there because you might pick one up before June and you don't know what that position is or who's going to get squeezed out of another club. There's always that uncertainty."
