Ottio spent two years with the Green Machine where he became a prolific try scorer for Mounties in the New South Wales Cup.

The 23-year-old was impressive for Papua New Guinea during the Rugby League World Cup and was slated to return to Raiders camp in a bid to earn a new deal following the tournament.

But Widnes came knocking and the former Papua New Guinean volleyball player leapt at the chance to establish a place in a top grade side.

Widnes coach Denis Betts says he is excited by the quality Ottio will bring to the Vikings' backline as they look to improve on a tough season that had them flirting with relegation.

"Kato is a fantastic signing, who we are delighted to welcome to Widnes Vikings," Betts said.

"He is a big outside back, with World Cup experience. I am excited by the quality that he will add to our edges.

"He is relishing his opportunity to play in the Super League, and is looking to make a big impression at Widnes Vikings.

"Kato is a player whose qualities we have seen during the World Cup. I have also spoken to several people in the NRL and connected to Canberra Raiders during my time at the tournament, who rate him very highly.

"It is exciting for us to follow the recent signing of Krisnan Inu with another talented outside back, who will add competition and quality to the team."

The Raiders are still looking for a hooker after first-choice rake Josh Hodgson ruptured his anterior cruciate ligament in England's World Cup semi-final triumph last weekend.

The Raiders have been linked to Samoa hooker Siliva Havili and Ireland rake Micky McIlorum as coach Ricky Stuart searches for a replacement for Hodgson, who will miss the bulk of the 2018 season.

Canberra's back-up No. 9 Adam Clydsdale quit the NRL just days before Hodgson's injury but the 24-year-old won't be tempted out of retirement.

Kurt Baptiste is being shopped around and could be on his way to the English Super League as the Raiders look to become salary cap compliant.

Offloading Baptiste should be enough to make the Raiders compliant as preparations ramp up for the 2018 season.