An online dating service encouraging extra-marital affairs has offered to sponsor the Cronulla Sharks in a deal worth more than $10 million.

International social networking service Ashley Madison – whose company slogan is "Life is short. Have an affair" – has prepared a record sponsorship offer to the cash-strapped club.

The Cronulla Sharks face a fine of $1 million if the NRL’s provisional sanctions become permanent. Credit:Getty Images

In a letter to Sharks chief executive Steve Noyce – obtained by Fairfax Media – Ashley Madison founder and chief executive Noel Biderman outlined a proposal which included covering a $1 million fine provisionally imposed by the NRL over the club's supplements program in 2011 in return for naming rights sponsorship on their jersey.

All up, the deal is worth $11 million over a decade. It's the second time Ashley Madison has attempted to get into bed with the Sharks. In May of 2012, the Canadian company tabled stadium and naming rights deals worth a combined $500,000, with bonuses if the Shire team made the finals or grand final. After careful consideration, the previous Sharks board and management rejected the proposal because of concerns the partnership would damage their brand.