A London court has been played a tape recording in which a sports agent accused of taking bribes to fix matches claims Australian cricketers are the "biggest" culprits in match fixing.

Agent Mazhar Majeed was covertly taped making the claim during a conversation with an undercover journalist from the now defunct News of the World Sunday tabloid.

The tape was played in Southwark Crown Court at the corruption trial of former Pakistan captain Salman Butt and fast bowler Mohammad Asif.

At the time of the conversation, reporter Mazher Mahmood, the former investigations editor for the newspaper, was posing as a rich Indian businessman seeking major international players for a new tournament.

Mr Majeed told Mahmood Australian players would fix "brackets", a set period of a match on which punters bet, for example, on how many runs will be scored.

Sorry, this audio has expired Court hears Australian cricketers 'biggest' match fixers

"The Australians, they are the biggest, they have 10 brackets a game," Mr Majeed said on the tape played to the court.

He said match fixing had been happening for years, and also named some of Pakistan's best-known former players as being involved in betting scams.

"It's been happening for centuries. It's been happening for years. Wasim, Waqar, Ijaz Ahmed, Moin Khan - they all did it."

Cricket Australia's general manager of public affairs Peter Young described Mr Majeed's statement as an "outlandish and bizarre claim from a person of dubious repute."

But he told AM that Cricket Australia would support any investigation into the allegations.

"We were very surprised to say the least, to hear of these outlandish claims," he said.

"It comes as news to us. Nevertheless, if anybody can provide a credible claim relating to cricket we support the view that it should be investigated with vigilance."

Australian Cricketers Association chief executive Paul Marsh also dismissed the claim, saying he did not believe Mr Majeed had any credibility.

"Our players are paid very well, they're educated very well, and I think our guys understand the consequences of getting involved here in this space; it's just not in the Australian culture," he said.

Former Pakistan captain Salman Butt outside an anti-corruption tribunal in Doha in February. ( Mohammed Dabbous : Reuters )

On the tape played to the court, Mr Majeed is heard telling the reporter he could make him "absolute millions" from match fixing.

A video secretly filmed in a car showed the agent and the reporter meeting on August 18 last year on the first day of Pakistan's Test against England at The Oval.

Mr Majeed said he would give the journalist proof of his influence by arranging for two no-balls to be bowled, for a fee of 10,000 pounds ($15,700) each, then said a "deposit" of 150,000 pounds was required for further activity.

"I will give you a bracket for the following day ... in terms of a deposit it is going to be 150,000 pounds minimum," the agent said.

"That is going to be for me to pay my six boys a certain amount each. After that I can give you everything we do and every result we do, every bracket we do."

Sorry, this audio has expired Cricket Australia to investigate match-fixing claims

Mr Majeed said he would pay the players to secure their cooperation.

He promised: "I have got the main players. I have got the bowlers and the batsmen and the all-rounders, I have got two-two-two and that is all you need.

"We have got one result already planned and that is in the next three matches, Pakistan will lose.

"Again you know as a cricket game it goes backwards and forwards, it is your responsibility to put it (a bet) on at the right time."

The agent said he would inform Mahmood of "exactly what the players are going to do".

"They will do their job," he promised.

Ironically, Mr Majeed told the journalist: "I know you and I have met you and I'm very good with people and instincts. I believe you are genuine."

Mr Majeed boasted that he knew Hollywood film star Brad Pitt and former world number one tennis player Roger Federer very well, and could arrange for them to promote the new cricket tournament.

Prosecutors allege Mr Majeed conspired with Butt and Asif to fix parts of the Lord's Test between England and Pakistan in August last year.

Butt and Asif, who are standing trial, deny the charges. The trial continues.