Wasps have signed All Blacks fly-half Lima Sopoaga for the 2018-19 season from Super Rugby side Highlanders.

The 26-year-old, who has played 16 Tests for the All Blacks, will effectively rule himself out of selection for the 2019 World Cup.

"It was one of the hardest decisions I've ever had to make but is one I'm at peace with," he posted on Instagram.

All Black selection policy dictates that players at overseas clubs are not considered for the national team.

Sopoaga has mainly been used as back-up to first-choice fly-half Beauden Barrett.

New Zealand head coach Steve Hansen said he was disappointed but understood Sopoaga's reasons for leaving.

"Our job now will be to develop the next player to take his place," he said.

Sopoaga has scored 55 points in 16 appearances since making his All Blacks Test debut against South Africa in July 2015.

He has also made 74 appearances for Dunedin-based Highlanders since making his debut in 2011, helping them to their first Super Rugby title in 2015, when he weighed in with a personal club record haul of 191 points.

Wasps director of rugby Dai Young said: "When a world-class fly half became available we jumped at the chance, as that doesn't happen very often.

"Lima's track record with the All Blacks, Highlanders and Southland speaks for itself."