RUGBY LEAGUE player salaries have slipped since the end of the Super League war - while footballers in rival codes are reaping huge increases in their annual incomes, with the prospect of more to come.

The average annual salary for the top 25 players at NRL clubs this year will be $164,000, down on the average of $226,000 paid by the top five clubs in 1999, according to research by Braham Dabscheck, a University of Melbourne academic who has been analysing professional team sports for three decades.

Dabscheck argues elite league players have been forced to wear a pay cut of 27 per cent - while their competitors in rugby union have reaped a rich harvest from the advent of the professional game, with their salaries jumping from $124,000 to $224,000 in the same period, an increase 81 per cent.

AFL salaries are up by 68 per cent, and football clubs, with the introduction of the A-League, have more than doubled payments to players under the old NSL, Dabscheck reports.

The NRL consistently defends its salary cap as an essential weapon in the fight to rein in costs and prevent clubs from going broke.

"However, unlike the other three football codes, its salary cap has not been linked to revenue," Dabscheck said. "The problem with a sporting league that adopts a policy of cost minimisation rather than revenue maximisation is that it reduces its ability to grow the sport."

Dabscheck's argument is the NRL is engaged in a process of ever-diminishing returns if it continues to concentrate on costs.

"They're cost minimisers rather than revenue maximisers, and the only asset they've got to maximise revenue is players," he argued. "But the thing that sells the sport is players. By keeping costs down, and in fact encouraging players to go elsewhere, what you're doing is reducing your ability to market your sport."

In rugby league's centenary year, the share of the game's revenue flowing to players has hit an all-time low. According to league historian Sean Fagan, at the game's inception, league clubs paid more than 90 per cent of their revenue to players. The pattern continued for decades, with takings being shared at the end of the season at a "Pay Out Night".

"The club secretary would call up all the players and they would each be given their bonus cheques - this was a division of the club's income from gate receipts, and players received a share based on how many games they played," Fagan explained.

"Effectively, each rugby league club ended the season broke."

In the 1970s, according to Ken Arthurson, secretary of the all-conquering Manly club, the lion's share of revenue went to players. "Really, there wasn't too much expenditure other than that - there was myself and a secretary," Arthurson said.

Even when then NSWRL supremo John Quayle first proposed a salary cap in the 1980s, the intention was that 75 per cent of revenue should flow to players. (In the 1980s, the majority of clubs were teetering on insolvency.) Under the existing salary cap, the poorest Sydney teams - with annual revenue of $11.5 million - spend only just over one-third of their income on their top 25 players, with the cap of $4.1 million preventing them going any higher. At the game's strongest club, Brisbane, one-fifth of revenue is returned to players.

Instead the money flows to coaches, support staff, training facilities and administrative personnel - with their share of the game's turnover rising at a dramatic rate, in part, argued Fagan, because of the salary cap.

"The cap only stops them spending money on players; it doesn't stop the space race with everything else. If you can raise $15 million, you'll spend $15 million and if you can only spend $4 million on players, you'll find somewhere else to spend it," he said.

Arthurson, a fan of the cap, noted the huge staffs all clubs employed. "I don't know how much money they pay them but their expenses have gone up astronomically," he said.

Dabscheck said the NRL should be opening the game to further investment by allowing a wider interpretation of third-party sponsorships of players, arguing the rules "push away parties that would like to invest in the game".

"You could still have a salary cap but if you enabled investors to 'top-up' player salaries, that would bring more money in," he said. "The problem is there would be income inequalities, but you could solve that by redistribution from the league's broadcasting deals."