The St George Illawarra Dragons have announced the long-term contract extension of Zac Lomax.

Already contracted for the 2020 season, Lomax has re-signed with the club for five years and will remain with the Red V until at least the end of the 2025 NRL Telstra Premiership season.

The Temora Dragons junior has been contracted to the club since he was 13 and is a graduate of the St George Illawarra junior pathway following his NRL debut in Round 10, 2018.

The two-time Junior Kangaroos representative and former Australian Schoolboy and NSWRL Under-18s Player of the Year has since played 17 first grade games.

Lomax said he was excited to confirm his future with St George Illawarra, in what is a period of learning for the 20-year-old as he navigates pre-season training with the intention of commencing the Dragons' 2020 campaign at fullback.

"Being able to go back to Temora at Christmas knowing that my future is settled and that I'm definitely going to be a Dragon for a while yet is very exciting. My family and I are very happy with the decision that's been made," Lomax said.

"With 2020, I've attacked every session possible and soaked up as much information as I can when it comes to playing fullback. I realise I still have a lot to learn but it's a challenge I'm really looking forward to."

Director of Rugby League Pathways and List Management Ian Millward hailed Lomax as a significant retention for the Dragons' on-field fortunes and succession planning.

"There was a lot of speculation over Zac with numerous clubs in for him and we respected the process he and his management went through," Millward said.

"One thing that hit home over the past couple of weeks was that he wanted to be a Dragon and wanted to stay at the Dragons.

"To have him recommit long term is a no-brainer. Our aim now, and Zac's, is to have him wear the Red V for the rest of his career – he wants to be a one-club player.

"Zac is already the benchmark at training. With his attitude and attention-to-detail we see him as a future leader of our club. The cherry on top is he's an outstanding goal kicker so we are pleased to shore that up too."

The Dragons have also announced that Hayden Lomax has signed a one-year development player contract extension which will keep him at the club until at least the end of the 2021 season.

The utility forward said he is keen to make up for lost time following an injury disrupted 2019 campaign.

"I'm so thankful for the opportunity to be given another season. I had an interrupted season last year so I'm very grateful," Lomax said.

"I never had an opportunity to play too much footy in 2019 so hopefully I can put my best foot forward and play consistent football in 2020.

"The club has been unreal to my family and I since arriving at the club when I was 15 and I've really appreciated everything since."