The guidelines, published on Wednesday and hailed as the biggest change to the treatment of the disease in almost a century, could result in more type 2 patients going under the knife to curb their weight gain and control their blood sugar levels.

Critics have argued surgical options - which bind or remove a portion of the stomach or intestines - could be seen by patients as a quick fix, and derail efforts to encourage lifestyle changes, such as diet and exercise, to manage the condition.

The joint statement endorsed by 45 medical and scientific groups, including Australian experts, recommends surgery as standard treatment for obese type 2 diabetes patients - with a BMI over 35 - who can't control their blood sugar levels through other means.

"These patients should be told that they are not just eligible but recommended for this surgery. Caring doctors should tell them," said physician and diabetes researcher John Dixon at Baker IDI Heart and Diabetes Institute.

"It's the responsibility now for health services to include this as standard therapy for these patients," Professor Dixon said.

While, type 2 diabetes is most prevalent among lower socioeconomic groups, the surgery costs upwards of $9000 and is almost exclusively offered in private hospitals.

By 2030, the number of people with diabetes worldwide is expected to rise to 472 million, according to the International Diabetes Federation.

An estimated 1.2 million Australians have been diagnosed with type 2 diabetes - the vast majority of whom are overweight or obese. Type 2 diabetes accounts for 60 per cent of the roughly $1.5 billion a year the healthcare system.

Medicare currently covers some bariatric surgeries, such as gastric bypass surgery and laparoscopic banding surgery for conditions related to morbid obesity.

"We've got to shake up our public hospital system in each state and remove the barriers that are preventing people for getting this treatment," Professor Dixon said.

The guidelines - which also suggest gastrointestinal surgeries should be considered for patients with a BMI of 30 and over if they can't control their hyperglycaemia with insulin - were based on a robust body of research, including 11 clinical trials over the past decade.

The trials showed the surgery improves blood glucose control more effectively than any lifestyle or pharmaceutical intervention, triggers dramatic weight loss and leads to long-term remission, the group of international experts said.

"This is the greatest departure from mainstream treatments of diabetes perhaps since insulin was introduced," said the Professor Francesco Rubino, chair of metabolic and bariatric surgery at King's College London, in an accompanying editorial published in the journal Nature.

"The evidence that surgery can prompt the remission of a disease long considered irreversible could bolster searches for what causes diabetes and even reinvigorate hopes to find a cure," he said.

The expert group recommended health regulators introduce reimbursement policies to support the approach, but government-subsidised bariatric surgery for type 2 diabetes has become a contentious issue in Australia and internationally.

Opponents have suggested that the invasive and costly procedures could disinsentivise people from making changes to their lifestyles, such as exercising and adopting healthy eating habits, to control or reverse the disease.

Diabetes Australia warns weight loss surgery should be a last resort, and only considered for very obese adults with a BMI over 40, or over 35 with an obesity-related medical condition.

"It's simply discriminating and stigmatising. People are not given the opportunity because they're told it's their fault, they just need to eat well - but we know this is just not the case," Professor Dixon said.

Despite the steep upfront cost of the surgery, the health system would benefit financially by eliminating the long-term burden of treating ongoing, poorly managed type 2 diabetes, he said.

One study published in the Medical Journal of Australia suggested the cost of the operation and follow-up was offset within a year.

Australia Diabetes Society president Sof Andrikopoulos, who endorsed the guidelines, cautioned that metabolic surgery "should be considered as an option - not necessarily the first option - for these patients".

"Diabetes and obesity are lifelong diseases, so we need to consider the impact of diabetes of health and economy in the long term," Associate Professor Andrikopoulos.said.