ONE of the oldest sponsorship deals in the NRL is over with the Parramatta Eels and Pirtek to part ways at the end of 2013.

Pirtek's decision to walk away after the Eels due to the raised cost of naming rights and jersey-front sponsorship continues the exodus of sponsorship dollars deserting the NRL in the wake of the ongoing investigation by the Australian Crime Commission into drugs in Australian sport and its links to organised crime.

Eels chief executive Ken Edwards this morning issued a statement to announce the nine-season sponsorship partnership will end at the end of this season.

"Whilst it is unfortunate that we couldn't come to terms to extend our current deal with Pirtek, I think it is important to celebrate what has been a wonderful association between the two parties,'' Edwards said.

"All our discussions leading up to making this decision were conducted professionally, which is a credit to what both Pirtek and the Parramatta Eels stand for.''

It is understood a three-year sponsorship deal between the two parties expires at the end of this year, with the Eels demanding an increase of $500,000 per season to a total of $1.5 million for naming rights and jersey-front branding.

There have also been lingering issues surrounding the relationship between the Parramatta football club board and Pirtek boss Glenn Duncan, who resigned from the board in 2011 over the club's financial position under former chief executive Paul Osborne.

Pirtek will maintain its corporate association with the Eels.

"Pirtek have enjoyed a fantastic association over the last nine years through both the highs and lows but our support for the club has never wavered,'' Duncan said.

"We wish them every success for the future in implementing their strategic plan over the next five years. We are looking forward to a great 2013 season, on and off the field."

It remains unclear who will take over from Pirtek as the club's major sponsor from next season.