Experimental therapy for type 2 diabetes zaps a nerve to influence glucose production in the liver.

Patients in New Zealand have become the first in the world to receive an experimental treatment for type 2 diabetes that relies on damaging a nerve that influences the liver.

If it proves effective, the nerve-zapping therapy could change the lives of tens of thousands of New Zealanders who face insulin injections to reduce their risk of blindness or other serious complications of the disease.

New Zealand is in the midst of a diabetes epidemic. More than 200,000 people been diagnosed with type 2 diabetes and it is estimated that more than half of them do not have good blood-glucose control, despite adopting a healthier lifestyle and taking pills to control the disease.

The next step for many may be insulin injections, but the risk of hypoglycaemia - dangerously low blood-sugar levels that can cause unconsciousness - deters some because it can make it harder to retain a licence for commercial driving.

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The experimental therapy, called hepatic denervation, will be used on up to 30 patients in a clinical trial at four hospitals in Auckland, Christchurch and Dunedin, that is scheduled to run until next March.

Three have been treated and follow-up data have been gathered on two, although one of the researchers said too little time had elapsed for a full assessment.

There had been some improvement in glucose levels, said Dr Brandon Orr-Walker, a diabetes specialist and investigator for the trial at Auckland's Middlemore Hospital.

"We are struggling with our current treatments to be able to manage things. We really are very keen to look at additional therapies that might have some extra benefit for patients."

The therapy uses radio frequency energy to damage the hepatic nerve, which influences production of glucose in the liver.

The energy is delivered in several doses from inside an artery near the liver via a catheter.

In a procedure with similarities to angioplasty for a heart attack, the catheter wire is threaded into the blood vessel through an incision at the groin.

Blood flow prevents the artery wall from heating up and only the adjacent nerve is damaged.

Trial patient Shane Solomon, 44, an Otago motorcycle-delivery van driver who was diagnosed with diabetes in 2010, said his glucose level rose after the treatment and then began to fall.

"I was being managed okay on oral medication [beforehand] but lately I have reached the limit of the amount of oral medication I can take."

His doctor had told him that despite exercising and improving his diet, his diabetes was poorly controlled and the next step would be insulin injections. But he didn't want the "extra hoops" he'd have to go through as a commercial driver.

Dr Orr-Walker said the trial followed studies in the United States that had shown the therapy was effective in animals.

He said although liver production of glucose was beneficial in healthy people, it could harm diabetics.

"A lot of our patients are on optimal oral medication and go to bed at night and the liver is producing more and more glucose so they wake up with more hyperglycaemia."