The Health Minister is refusing to back down from the success of his bowel screening programme, releasing figures to show it's working.

Jonathan Coleman has been caught up in a back-and-forth with Treasury, over whether the case for the screening programme was rushed.

Dr Coleman said May 2016 saw the highest ever numbers of patients receive a colonoscopy, while wait times are down 27 percent compared to 2014.

"There's more colonoscopies being done, people are waiting shorter periods, so it's literally a lifesaver for New Zealanders."

Treasury advice shows they warned against the programme, and that it was risking failure by being rushed.

Dr Coleman doesn't agree.

"Frankly, I don't think Treasury are seeing the big picture here. It's not just about the money, yes of course you have to get value for money, but this is actually about saving Kiwi lives."

But Labour's health spokesperson Annette King argues the touted improvements to the bowel screening programme are meaningless.

It only looked good because of the huge delays the system was dealing with before, she said.

"So the fact that they might have improved came about because of the big waiting lists that there already were, it had nothing to do with bowel screening."