Teenage talent Karl Oloapu has signed a four-year NRL deal with Canterbury to finalise a messy divorce with Brisbane.

The 18-year-old will join the Bulldogs, who paid the Broncos a transfer fee for the former Australian schoolboys captain, immediately.

Oloapu had been in the Broncos' system since he was 13 but refused to train late last year and claimed he would never play for the club because of "broken promises" in a new, three-year deal brokered by a previous manager.

The Broncos initially held their ground as they urged him to return to Red Hill, recruitment chief Simon Scanlan saying the NRL and Rugby League Players Association had reviewed Oloapu's contractual situation and "no wrongdoing by the club was found".

The stand-off continued into 2023 and Brisbane eventually allowed Oloapu to meet with rival clubs, reportedly placing a $500,000 fee on his head.

"The Bulldogs would like to acknowledge the Brisbane Broncos and the development work that they have already put into Karl's career," a Canterbury statement said.

"We would like to thank the Broncos for their professionalism in dealing with this process and in providing Karl with the early release to pursue this opportunity."

Brisbane chief executive Dave Donaghy described the transfer as a "unique situation".

"We are comfortable with the position we have reached with the Bulldogs and as a result, we have granted Karl an early release" he said in a statement issued on Friday.

"We wish him well for the future."

Oloapu said he was grateful to the Broncos' development system and thanked the club for their decision to release him from his contract.