Auckland's privately owned radiation therapy clinic has introduced a treatment expected to improve the control of tumours and reduce harmful complications.

Auckland Radiation Oncology says it is the first clinic in New Zealand or Australia to adopt the technique, which requires additional software and staff training.

Public-hospital cancer centres are likely to introduce the same or similar technology within months.

Called volumetric modulated arc therapy or VMAT, it delivers the same quantity of radiation but potentially more accurately than existing techniques and is much faster.

Instead of shooting radiation at the tumour from static positions around the patient, each requiring set-up time, the radiation beam is fired as the large machine, swivel-mounted on the wall, moves in a continuous orbit. Three-dimensional CT scanning technology increases the precision.

With VMAT, prostate cancer treatment has been trimmed to sessions lasting just 100 seconds.

Previously, patients had to lie completely still with a full bladder, which helps to position internal organs, for seven minutes.

Only prostate cancer patients are being treated with VMAT yet, but pancreatic and lung cancer patients will be included once the clinic's third treatment machine is installed.