The head coach of the Cronulla Sharks has been accused of using a bank account off the club's books.

At the same time, an internal report into the club's supplements regime has been obtained that says prohibited peptides were given to some players in 2011.

In an exclusive report by the ABC's 7.30 program, it reported head coach Shane Flanagan operated what was called a high-performance unit (HPU) bank account despite the NRL club's board ordering it be shut down.

The program also obtained emails in which a former sponsor claims cash payments were made to captain Paul Gallen outside the salary cap.

Former Sharks chief executive Bruno Cullen, the man who was called in to clean up the mess after Cronulla's secret supplements regime exploded in public scandal, has described the club's administration as a disaster waiting to happen.

"You just don't do things that way, no," he said.

"Every dollar that comes into the club, and therefore every dollar that goes out of the club, should going through the club's central account and be recorded and accounted for."

7.30 understands the HPU account was operating outside of the board's control after being ordered to shut down.

Flanagan told 7.30 yesterday that it was used to pay for the club's new gym.

Cullen said he never knew of the account.

"No, not at all no. The club didn't even bank with Westpac, they banked with St George."

Deal being done in private

7.30 has also obtained a series of emails that expose a deal being done in private at the Sharks.

They were written by Sami Chamoun, a former Cronulla sponsor and director of security company E Group.

On February 5, 2013, just days before the Sharks' secret supplements regime became public, Chamoun wrote to the Cronulla board complaining about his contract being terminated early, threatening to blow the lid on a secret salary cap deal.

I've been paying a certain player cash off the salary cap for the past three years, you think that's not going to get out into the media if it goes into a legal case.... It's the truth, you and your management have a lot to answer.

Half an hour later, a furious Flanagan wrote to the board seeking help, revealing the identity of the player and the club's breach of the salary cap rules.

That player was NSW's favourite son - Blues captain and Cronulla chief Gallen.

Tonight Paul Gallen has been contacted and informed by Sami of E Group... and give(n) (sic) his account of contract details with our club and full details of payments to Paul over many years which will expose us salary cap and Paul possibly taxation wise... this will not go away unless dealt with tomorrow and this is a lot bigger than a security contract.

7.30 understands it was not Gallen but the club that was in breach.

It is believed payments to a number of players run up to $250,000 and were never properly registered as third-party player agreements.

"I know cash sounds terrible, and that's something I won't go there with that, but the arrangement was for him to make a payment to Paul, do the sponsorship and make the third-party payment," Cullen said.

"Now whether he paid that by - and I don't want to sound flippant - by cash, by cheque, by jars of vegemite, whatever, he made the payment.

"But the problem is more the documentation of that from a salary cap point of view, it wasn't formalised the way it should've been."

Report reveals banned substances used

Exposure of the secret bank account is not the only scandal hanging over the club.

With ASADA's interim report into the supplements regime run by sports scientist Steve Dank at the Essendon AFL club now complete, the regulator has turned its attention back to the Sharks.

After its first attempts to interview players about the alleged use of peptides during Dank's tenure failed, two weeks ago ASADA recommenced proceedings.

In May, Wade Graham arrived for his interview wearing thongs and a t-shirt before reportedly refusing to answer any questions.

But now, bolstered with new powers to compel witnesses to answer questions, the regulator is expected to get much further this time around.

While Dank maintains he never gave any players prohibited substances, 7.30 has obtained an internal report on the Sharks completed in March by Dr Trish Kavanagh, formerly of ASADA, which has never been publicly released before now.

It shows that during Dank's five-month tenure in 2011, players were injected with peptides GHRP6 and CJC-1295 four times before being administered cream versions.

Kavanagh's report states that both peptides were prohibited from January 1, 2011.

"Everyone that was around the club, including Steve Dank and other people at the club at the time, had a real responsibility for the players' welfare," Cullen said of that period at the club.

"I don't believe that that was that focus was anywhere near what it should've been."

Survival rests on righting wrongs

For Cullen, the survival of the Sharks rests on the club righting the wrongs of the past and ensuring they do not make the same mistakes again.

"I'm not too sure whether they've learnt their lesson or not," he said.

"Worst-case scenario, I fear for them and a whole lot of things about player suspension, players suing the club for loss of income, players suing the club for player welfare.

"Best-case scenario, they'll be fine. They have the commercial development to fall back on.

"Worst-case scenario, they are going to have some huge challenges."