Overweight women in South Auckland are having to wait longer than others for a diagnosis of gynaecological cancer.
The Counties Manukau District Health Board said women with a body mass index over 40 were facing delays to the procedures needed to diagnose the cancers.
That was partly because the women were more likely to need an operating theatre for the work and that took more time and needed more resources and staff.
Theatre access had become "problematic", the DHB said in a report.
The Cancer Society said the delay was unacceptable and the women should have quick access to diagnoses no matter what their size.
Its medical director, Dr Chris Jackson, said the DHB needed to provide services that met the needs of its patients and it had to adapt as its population changed.
Counties Manukau has 36,000 morbidly obese people in its area, more than any other district health board.
The DHB has said in the past that means treatment can be more complex and take more time.
Jackson said the problem was not limited to Counties Manukau or to any one type of cancer.
"We have to tackle this problem head on otherwise people are going to suffer, people's diagnoses are going to be delayed and people are going to die as a result."
The DHB said about 18 percent of the women facing delayed diagnoses would be found to have cancer.
Its report said one woman waited 53 days, although it did not specify whether she was in the high body mass index group.
Jackson said it was difficult to say what the impact would be on the women's long term health if she had cancer, because it varied from cancer to cancer and case to case.
But it was incredibly stressful waiting to find out if you could have cancer, and to wait 53 days was unacceptable, he said.
"I meet people every single day who are waiting for cancer diagnostic tests who tell me of the distress they are under... every single day their life is on hold until that happens."