The new deal will see Ofahengaue remain a Bronco until at least the end of the 2019 NRL season. 

Ofahengaue, 21, has already made 40 NRL appearances for the Broncos, including the 2015 NRL Grand Final. 

He has also represented Tonga at senior level, and his re-signing is a major coup for the Broncos. 

"Joe showed us just how much promise he had when he played an NRL grand final in his first season of NRL at age 20," said Broncos chief executive Paul White. 

"We have always seen him as an important part of our future.

"To have him sign a two-year deal is wonderful news for the club, our members and our supporters."