National's mental health spokesman Matt Doocey says it's disappointing the Labour and the Greens have declined to work across Parliament on mental health before a major inquiry reports back.
Doocey wrote to Health Minister David Clark and all other MPs in July, calling for cross-party collaboration on what he called "one of the biggest challenges of our generation".
Doocey said today it was clear from a letter Clark sent him that he had ruled that out.
"He's actually ruled it out because he's made it very clear that he believes cross-party work is best done in a select committee. The minister is either being disingenuous or has misunderstood the role of a cross-party group," Doocey said.
"We can find common ground and that's what I believe the public is expecting of us on a big issues like mental health, and it's disappointing that we have a health minister who's not interested in looking into that," he said.