Sims was to come off contract next year, but the new deal keeps him in Wollongong until at least the end of 2022.

The Gerringong junior made his State of Origin debut for NSW this year and also scored three tries in the Dragons elimination final demolition of Brisbane.

Sims, who has been nominated for the Illawarra Mercury sportsperson of the year award, has previously played for North Queensland and Newcastle, but said he had a premiership in his sights with the Dragons.

“The Dragons has always been a club I've wanted to play for and represent being from Gerringong. To have the chance to extend my time with this special playing group, it was too good an opportunity to go anywhere else," Sims said in a statement.

"Mary (Paul McGregor) is a coach I've always wanted to play for and he has always wanted to coach me, which was very important when I first came to the Dragons. I'd like to think I've taken my opportunities here at the club with both hands.

"The goal is always winning a premiership, but I can't wait to help develop the players coming through," Sims added.

"To see some of these young kids kick on in their careers from the Under-20s to the NRL in the coming years will be a real highlight."

Meanwhile, the Dragons have also signed former Brisbane Broncos outside back Lachlan Maranta on a one-year deal.

Maranta has played 70 NRL games to date, and has spent the past two years at Super Rugby outfit, Queensland Reds.

"Lachlan has played plenty of NRL games over a period of five seasons and proved he was versatile across the outside backs. He's proven so far to be a really good person who trains well, and he'll bring experience to the squad," Millward said.