Former Ospreys chief Mike Cuddy says the Welsh Rugby Union must give more money to Cardiff Blues, Ospreys, Scarlets and Newport Gwent Dragons.
"The national/regional environment and relationship is not what it should be," he said.
The WRU declined to respond directly to Cuddy's criticism.
But a WRU spokesman said: "Our priority is to continue the active and positive debate which is currently taking place."
Cuddy, who helped form the Ospreys in 2003, says the quartet underpinned Wales' 2005, 2008 and 2012 Grand Slams.
"It's fact that the national/regional environment and relationship is not what it should be," said Cuddy, who wished to emphasise he was speaking personally and not on the Ospreys' behalf.
"Sometimes, it's like Wales has five regions rather than four with the national team at the top of the Welsh rugby pyramid, more competitor than friend, role model, mentor or father figure."
The regions each receive £3.5m annually from playing in televised competitions combined with a share of £6m from the WRU.
However, in recent seasons the regions have lost a host of Welsh and non-Welsh players to French and English clubs, having introduced a £3.5m annual salary cap.
French-based Grand Slam and 2011 World Cup stars James Hook, Mike Phillips, Gethin Jenkins, Lee Byrne and Luke Charteris are among those to have left amid the financial constraints.
The WRU and the four Welsh regions' financial review by accountants PricewaterhouseCoopers of professional rugby has been completed.
And an announcement on the report's findings is expected in the coming weeks.
It will be made in the wake of the WRU recording revenue of £63m in the last financial year, its highest ever turnover.
According to the WRU's recent annual statement, the Millennium Stadium debt, which was around £75m when the ground was built in 1999, is now £19m.
Cuddy predicts the PricewaterhouseCoopers report "won't make pretty reading", adding: "All we seem to get at the regions is calls for more release time to the national team for our top players and demands that they should be paid more wages to keep them in Wales.
"All the give for the past 10 seasons has been on the side of the regions.
"Yet all the plaudits seem to have been taken by others.
"If the top Welsh players are to play and stay in Wales, it [the WRU's relationship with the regions] has to change.
"A mere £6m of the WRU's earnings are returned to the regions in real terms.
"The rest is merely a case of them handing on TV rights for the regional game, funds that belong to the four teams involved at that level".
Cuddy says the formation of regions under WRU chief executive Roger Lewis' predecessor David Moffett helped transform Wales' fortunes.
"The last 10 years have been a constant battle for survival," he added.
"And there's absolutely no doubt that had it not been for the backers, none of the regions could have survived.
"The regional era has seen three Welsh Grand Slams, the first, in 2005, coming an astonishing 27 years after the previous one, in 1978! What changed?
"What created a changed environment that made a Grand Slam not just possible, but an actuality? It was regionalisation.
"And it needed an outsider like David Moffett, a unique character, to act as both architect and enforcer for a plan that would change everything forever.
"It may not be everyone's cup of tea, but the old village mentality and parochial tribalism of Welsh Rugby which I loved by the way, was never going to be sustainable in the modern, professional era.
"The Grand Slam of 2005 wasn't a coincidence and it wasn't a coincidence in 2008 and 2012 either.
"Yes the players were magnificent and yes, the Union did a wonderful job at international level, but the foundation and context was and is, a strong regional set-up."
Cuddy also criticises WRU boss Lewis' response to former Newport backer Tony Brown's views on the governing body's financial priorities.
Brown, who is on the Dragons' board, said the regions are being allowed to "bleed to death" while the WRU prospers.
Lewis responded by saying: "I think Tony is a bit lost in action here.
"He has only attended one meeting with the WRU and the four regions over the last six years - that took place this year.
"So, I didn't quite know what to make of Tony's comments there because we have been working hard with the people who are at the sharp end of regional rugby."
Cuddy said: "Tony Brown... was making a valid point.
"For me, it sparked the thought that the WRU's £63m turnover must be roughly equivalent to what the likes of myself and others at the Ospreys, and the small band of benefactors at the other regions, have probably ploughed into the regional game since 2003.
"I don't think that it's helpful when a man of Tony's stature is described as 'lost in action' or his viewpoint seemingly scoffed at.
"Tony has a right to speak. He's earned it.
"What he did at Newport immediately before the introduction of the regions set the standard.
"The fact that he has played a less visible role in more recent times will be more down to ill-health than anything else."
Scarlets chief executive Mark Davies has previously insisted the WRU and the regions are working together effectively to fund the Welsh game.
"We all believe - the regions and the WRU and the regions together - that working within the right structures together we can improve the health of the professional game whilst ensuring the health of the community game," he said.
"That's why it's taking time and that's why it's not as simple as moving money from A to B.
"If we simply move money from A to B anywhere within Welsh rugby it doesn't necessarily improve Welsh rugby."