"We're thrilled to have Ihaia with us for the next two seasons," Kirwan said.
"He's incredibly relaxed under pressure and has a great temperament that you need in a 10. Nothing seems to faze him; he came into the football team midway through the year but it was like he'd been here five years.
"He's brought a nice attacking edge to the team and hasn't tried to do too much too early and I think we'll see him continue to grow. We've seen enough of him to realise that, along with Simon Hickey who are quite different footballers, we've got two great 10s we can really build a franchise around."
West said his decision to turn down a Super Rugby contract in Australia last year to pursue his goal of playing in New Zealand had certainly paid off.
"At the start of the year I was a bit gutted watching Super Rugby on TV and thought what if I took that contract but getting the opportunity to play a few games with the Blues then securing a contract for the next couple of years, I'm certainly stoked with my decision now," West said.
"I've really enjoyed my time up here with the Blues. I've loved the environment, there's a great bunch of guys and coaches so I'm really excited to sign and I'm looking forward to the next couple of years."
The Blues play the Chiefs in their final regular season game on Friday night, needing to beat the defending champions by more than 38 points to keep their slim playoff hopes alive.