The best of Jarryd Hayne in his one NFL season with the San Francisco 49ers.

New revelations in an NRL breach notice against the Parramatta Eels reportedly show the club secretly arranged half a million dollars in deals for failed NFL convert Jarryd Hayne since 2013.

Official documents and boardroom minutes show a trail of salary cap discrepancies in the star fullback's third-party deals with the club from 2013 to 2015, Australia's Daily Telegraph reported on Tuesday.

The deals allegedly included cash payments, first class overseas travel and car expenses adding up to A$465,000 (NZ$498,890), all hidden from the NRL.

GETTY IMAGES Jarryd Hayne reportedly received half a million dollars worth of perks from the Parramatta Eels.

The revelations follow Hayne's surprise news on Monday that he was quitting the San Francisco 49ers and an American football career to chase Olympic gold with Fiji's rugby sevens team.

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Third-party payments to players must be done on an arm's length basis from the club and it's a breach of salary cap rules if a club makes a payment on behalf of third parties.

News Corp said there was no suggestion Hayne was aware his payments were contrary to NRL rules or that Hayne had done anything wrong.

When asked by reporters about the "secret deals" in London on Monday, Hayne joked about the amount.

"Half a million, wow, must have been the wrong bank account. I haven't seen it." When asked if he was aware of any off-the-record payments Hayne replied, "Not that I'm aware of, no".

In February, Hayne told Australian radio station Triple M that if he ever made a return to the NRL, he would want it to be with the Eels.

"Like I always said, if I ever came back, I'd go to Parra if they wanted me," he said.

On Monday, the 28-year-old was soaking up the sun in London as he waited to join Fiji's rugby sevens side in this weekend's international comp at Twickenham.

Returning to his hotel in Chelsea on a sunny Monday afternoon, a relaxed Hayne, who flew in from the US after quitting the NFL, told AAP he would talk to media later in the day or on Tuesday.

The Fiji team was due to arrive at the hotel later on Monday.

Hayne said in a statement on Sunday that the Olympics was "something I have admired since I was a little boy, and it is an opportunity I feel very similar to me joining the NFL".

The player is a hero in Fiji and has often talked of his deep connection to the Pacific nation and his life-changing experience with the national team at the 2008 Rugby League World Cup.

There was doubt over whether Hayne would be eligible to play at the Olympics in August, as he was switching from a code that did not comply with the international anti-doping agency, WADA, to a compliant code - which requires him to undergo a six-month testing period before competing.