Melbourne Storm star Suliasi Vunivalu will switch to rugby union from 2021 after signing a two-year deal with the Reds.

Vunivalu, 24, played union as a teenager before being signed by the Storm, where he made his NRL debut in 2016.

The Fiji international has scored 72 tries in 94 NRL games for Melbourne, helping the Storm win the 2017 premiership.

Vunivalu will honour the final year of his contract with the Storm before joining the Reds in 2021, it was confirmed on Tuesday.

"The Storm has been wonderful to me, and I'm continuing to make great memories here," he said.

"However, the offer from rugby union was too good for me to refuse, especially considering I have a young family who I want to do the best for.

"I was a rugby union player before switching to league and always thought going back to rugby was an option for my career and I never wanted to play for another NRL club.

"I'd hate to have to go up against Storm and my mates. Now this decision is public, I'm concentrating 100 per cent on my final year in Melbourne and looking forward to doing the best I can for the boys, the coaches and all our members and fans.

"I won't be making any further comments on rugby until the NRL season is done."

Vunivalu was the top try-scorer in the NRL in 2016 and 2017, crossing 23 times in each campaign.

Reds head coach Brad Thorn was delighted with the signing of the wing.

"As a group we look forward to welcoming Suliasi Vunivalu back to rugby and to Queensland in 2021," he said.

"Suliasi grew up playing rugby in New Zealand before becoming one of the NRL's most exciting players.

"He's an impressive talent and has an awesome ability to find the try-line. He brings good experience too with almost 100 NRL games for Melbourne and 12 rugby league Tests for Fiji. Suliasi will be a great addition to our programme."