The ink is barely dry on his new multi-million-dollar NRL contract, but Andrew Fifita has revealed his big plans to play rugby union.

Less than a month after signing a four-year deal reportedly worth more than $3.5 million to join Canterbury Bulldogs from Cronulla Sharks next season, making him the highest-paid prop in rugby league history, Fifita says a code switch down the track is inevitable.

Inevitable: Bulldogs-bound prop Andrew Fifita says he will play rugby union. Credit:Getty Images

The tearaway Kangaroos front-rower, who held discussions with Wallabies coach Ewen McKenzie late last year, says it's not a matter of if, but when he returns to the game he grew up playing - and loving.

In an extraordinary confession, Fifita even said he wished he picked rugby union over league this month such has been the flak he's copped for leaving the Sharks.