Australia's players will a $40,000 flat free for their participation in the tournament, which kicks off on Thursday.
The deal was previously struck as part of the collective bargaining agreement between the Rugby League Players Association (RLPA) and the Australian Rugby League Commission (ARLC).
But the sore point is that players from the other nations receive just $850 per match, with a maximum earn of $4250 for the tournament for players in a team that makes the final.
Dolphins forward Kaufusi, who represents Tonga on the international stage but is not in the squad for the World Cup, was appointed general president of the RLPA in November last year and will use his clout to bring fairness to the financial table.
"It is a tough one because it is international footy but that is definitely something I will address," Kaufusi told AAP.
"I want more equality in the prize money. It is something we will raise in the next CBA.
"Australia is always going to get first preference, which is fine, but we need to get to a stage where it is a lot more even.
"It may not be the same, but it should be somewhere thereabouts."
Several national coaches told AAP of their concern before the World Cup squads were named that Australia's pay deal may prompt some players to choose the Kangaroos over other nations in order to benefit their families financially.
Kaufusi said while the majority of players prioritised their international allegiance out of respect for their heritage and culture rather than money, a fairer financial system would take that lure out of the equation.
Ahead of the 2017 World Cup, current Tonga captain Jason Taumalolo chose the Mate Ma'a over New Zealand while former Cronulla prop Andrew Fifita joined him after previously representing Australia.
Both gave up the $20,000 on offer at the 2017 World Cup for players of both tier one nations at the time.
"Jason Taumalolo and Andrew Fifita both had to make the ultimate sacrifice," Kaufusi said.
"Jason is so inspirational and a lot of us boys look up to him.Â
"What he did for, not just me, but the benefit of all the younger guys coming through today like Robert Toia was awesome
"Robert can play for different nations but he is proud to play for Tonga."
Sydney Roosters centre Toia was in the sights of the Kangaroos ahead of this year's World Cup and had a tough call to make but ultimately elected to stick with the Mate Ma'a.
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