Brisbane chief executive Bruno Cullen has angrily hitout at unsubstantiated rumours of a salary cap breach involving third party payments which could damage his club's proud reputation.

The Broncos became the centre of a salary cap drama when prominent bookmakers across the country on Monday suspended wooden spoon betting following a series of bets on Brisbane to crash from premiers to last in 2007.

It was rumoured punters went on a betting spree armed with inside information that Brisbane would be stripped of premiership points for "back pocket" payments to a player not disclosed in the club's salary cap submission to the NRL last week.

The amount was rumoured to be $50,000.

But NRL chief executive David Gallop said his investigators had found no evidence of a breach, but would re-open their search if more information emerged.

"The NRL has made some inquiries in relation to the rumours but there's nothing at this stage to suggest the need for further investigation," said Gallop.

"However, if information were to come to hand that warranted further investigation then we would certainly take the appropriate action."

Bookmakers reacted to the NRL's clearing of the Broncos and re-opened betting markets on the wooden spoon on Tuesday.

Desperate to clear the club's name, Cullen invited the NRL's salary cap auditor Ian Schubert to further probe their records and declared Brisbane had nothing to hide.

He and Brisbane chairman Darryl Somerville signed a salary cap statutory declaration last week swearing the figure they had submitted were true.

A falsified stat could result in both men going to jail.

"I stake my reputation and my life on that being factual," said Cullen.

"This all started from the bet and somebody asking a punter why he'd have $1500 or whatever it was on the Broncos to win the wooden spoon at $71.

"The suggestion was that they'd heard the NRL was going to deduct points from us for a salary cap breach."

Cullen was bitterly disappointed the rumours surfaced just before the season kicked-off on Friday night against North Queensland.

"It takes away a bit from Friday but I'm more disappointed that it attacks the reputation of the club," he said.

"We've got a pretty good reputation and have had for some time in this regard and I've been proud of that.

"I'll keep saying it, I don't think there's anything in this but as you all know mud sticks.

"We've just announced an ongoing sponsorship today with NRMA and it damages your reputation to a degree with your fans, your corporate supporters and your sponsors.

"If that happens I'm very disappointed, I'm quite angry about it actually.

"I've had a couple of calls from sponsors, mostly supportive.

"They just want us to reconfirm it's all kosher, which you can understand."

The rumours can be traced back to an investigation into one of the club's leading supporters.

Multi-millionaire Ken Talbot, a member of the Thoroughbreds - a group of prominent businessmen who support the Broncos players with career and investment advice - is currently facing corruption charges.

Talbot and former Queensland Government minister Gordon Nuttall are each facing 35 corruption charges over secret commissions paid by Talbot to Nuttall totalling $300,000.

It was thought evidence may come out in the inquiry which could be damaging to the Broncos.

The prospect of a Broncos salary cap scandal prompted punters to act quickly with one gambler placing up to $2000 with NSW TAB Sportsbet on Brisbane to finish last at $71.

Sportingbet said they were first hit with a $500 bet on Brisbane going from first to last at $101 last week to lose $50,000.

They wrote another bet at $81 on Brisbane for a $100 wager before cutting Brisbane's odds to $51 and suspending betting after "smelling a rat".

Sportingbet's Bill Richmond said his agency had not taken enough on Brisbane to "buy a round of drinks" in 2006 to win the wooden spoon.

"For someone to be backing them to come last after they'd won the premiership you would have to think something was off," said Richmond.

Gerard Daffy from betting newcomers Lassetters Sports says "Broncogate" is nothing new thanks to people's love of a good betting scandal or rumour.

"We saw the same thing with the Sydney Roosters when they were backed from 100-1 to 20-1 in six hours on a rumour and punters got burnt," said Daffy.

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