Jarvis answers Welsh SOS
He is due to arrive in Auckland on Wednesday – ahead of the first of three Tests against the All Blacks.
James is still struggling with a calf injury and looks set to miss both this weekend's first Test at Eden Park and next Tuesday's clash with former Super Rugby champions the Chiefs in Hamilton.
"You always want a fully fit squad and Paul has been grafting hard to be fully fit particularly for the game on Tuesday," Wales assistant coach Shaun Edwards said.
"Unfortunately it doesn't look as though that is going to happen and we have brought Aaron out as cover," he said.
Jarvis, who is heading to Clermont Auvergne next season, trained with the Welsh squad for the two weeks before they travelled to New Zealand and was with the party at Twickenham when they played England 10 days ago.
Capped 17 times by Wales, the 30-year-old was a replacement in the final Six Nations game against Italy in March.
* In other injury news Wales captain Sam Warburton is close to overcoming a shoulder injury and being cleared to play on Saturday.
However, New Zealand looks likely to be without lock Sam Whitelock and reserve scrumhalf Tawera Kerr-Barlow.
Warburton's fitness has encouraged team management and his chances of being named on Thursday and playing in the first match of the three-test series have improved.
"His shoulder is improving quite dramatically and I think he will be there or thereabouts," Edwards said.
"I think Sam is one of the few guys possibly who can go into a game not having played for a few weeks and be pretty sharp.
"He's that kind of guy and keeps himself very fit and is working quite hard on his conditioning so we are hopeful that he is going to be up for selection."
New Zealand's Whitelock is recovering from a hamstring strain, and Kerr-Barlow who has a broken hand, and appear less likely than Warburton to be able to shake off the injuries for the first test.
