UPDATED 10.15am A Specialist Diabetes Physician hopes new international guidelines recommending surgical treatment for obese patients with type 2 diabetes, will encourage more equitable access to bariatric surgery in New Zealand.

LISTEN ABOVE: Dr Richard Barbor talks to Mike Hosking

Gastrointestinal surgery has been used as a weight management tool in obese patients, many of whom have diabetes, but hasn't been recommended as a direct treatment for diabetes until now.

It's recommending reducing the Body Mass Index surgery eligibility for those unable to control their blood sugar through other treatments.

Dr Rinki Murphy said now for the first time, international guidelines are recommending the surgery as a direct treatment for people with type 2 diabetes.

"I guess what these guidelines may improve is more representative referrals from the ethnic groups that are affected disproportionately, by both diabetes and obesity, and that's Pacific and Maori groups."

Dr Murphy said bariatric surgery should be routinely discussed with adult patients with high BMI.

"I think we need discussion around how low we make the threshold. As it is, we're not necessarily going to be able to offer bariatric surgery to all those people who qualify even at a higher body weight, so simply bringing that threshold down isn't going to improve that situation."

Bariatric surgeon Dr Richard Babor told Mike Hosking there's a big problem encouraging everyone to jump on the surgery bandwagon.

"In Counties Manukau that means 24,000 people or eight per cent of people so that will take 276 years to do all the diabetics in Counties Manukau."

The New Zealand Society of the Study of Diabetes has not fully endorse the guidelines because of limited public funding for bariatric surgery.

Spokesman Associate Professor Jeremy Krebs said they're concerned about the lack of emphasis on dietary intervention in those with a BMI of 30-35 prior to considering surgery.

He said it would be difficult to justify calls to prioritise this group, particularly for surgery.