Matthew Johns will auction off his 1999 Kangaroos jersey for junior rugby league club Picton Magpies.

Former Australia, NSW Blues, Newcastle Knights and Cronulla Sharks star Matthew Johns will auction off his Kangaroos jersey with all proceeds going to a flood-affected junior rugby league club.

Johns announced the auction on the Triple M Grill Team show in Sydney this morning.

"You hate to hear about junior rugby league clubs doing it tough, particularly all those effected by the floods, as far as all their equipment is concerned," Johns said.

The prize package up for auction includes Johns' 1999 Kangaroos jersey that he played five-eighth in, four tickets to watch The Grill Team live on Monday morning and four tickets to The Matty Johns Show at Fox Sports studios on Monday night. All items form one auction package, with the reserve price set at $4,000.

"I only played nine Tests, so this is a rare item," Johns said.

All proceeds will go to the Picton Magpies Junior Rugby League Club to help them buy equipment to replace the gear they lost in the recent Sydney floods. 

The auction will take place live on The Grill Team on Sydney's 104.9 Triple M tomorrow morning (Friday, June 17) between 8.00am and 9.00am AEST. Tune into The Grill Team tomorrow morning for more information and to bid on the auction.