Southland District Health Board's chief medical officer is so worried about cancer patients' treatment delays, he's offered to resign if things don't improve. Health Minister Jonathan Coleman says the problems are at an operational level.

"This is absolutely terrible, my sympathies are with these men. This is an unacceptable situation... This must never happen again. The urology service has to perform far better," Mr Coleman told Morning Report.

Replying to the question of responsibility, he says: "If you're asking if a politician should resign every time something like this happened, frankly that's not the right answer."

Mr Coleman says the problems are systemic and denies it is due to a lack of funding.

"Funding might have helped but it wouldn't have averted this tragedy," he says.