Health Minister Tony Ryall says district health boards are failing to meet cancer treatment goals and he will hold them accountable if waiting times do not improve.
A second batch of details on how well hospitals are meeting key health targets set by Mr Ryall last July is to be issued on Friday.
Eight of the 21 health boards have fallen back since the last quarter in their ability to provide radiation treatment within six weeks of a patient's first specialist assessment.
Mr Ryall says DHBs need to do a lot better, particularly in Auckland. He says some of the boards have told him the slowdown is due to increased patient numbers, but he says they should be able to cope with that.