Jaydn Su'A has parlayed career-best form into a two-year contract extension with St George Illawarra, ending speculation of a reunion with Wayne Bennett.

The second-rower had been off contract at the end of the season and told AAP in late March he was hopeful of staying at the joint venture, despite being linked with Bennett.

After being handed his NRL debut by the master coach in 2016, Su'A followed Bennett from Brisbane to South Sydney and played in the Rabbitohs' 2021 grand final side under the seven-time premiership winner.

He relocated to the joint venture a year later and is now shining for the improved Dragons under new coach Shane Flanagan.

Dolphins boss Bennett is all but certain to return to South Sydney from 2025 after the struggling club sacked his former protege Jason Demetriou in April, though a deal is unlikely to be finalised until next week.

The Rabbitohs could have done with a second-rower of Su'A's ilk, with Keaon Koloamatangi out of form on one edge and instability at the selection table on the other.

But Su'A is now set to stay put at the Dragons until at least the end of 2026 as Flanagan continues to rebuild the club's roster.

"Jaydn's performances this year have shown how important he is to this club and how determined he is to perform for the Dragons," Flanagan said.

"He is just coming in to his best football and we see him as a vital part of our forward pack over the coming years."

Su'A's Dragons teammates Tyrell Sloan, Jack de Belin, Tom Eisenhuth and Ben Murdoch-Masila remain uncontracted beyond 2024.

Su'A has played 123 NRL games to date and represented Queensland four times between 2020 and 2021. He was also a member of the Samoa side that finished the World Cup as runners-up in 2022.