There are calls for Australians with mental illness to be given greater access to controversial surgery that places electrodes in a patient's brain while they are awake.

Deep brain stimulation has been used to treat patients with Parkinson's disease for decades, but more recently it has been trialled on patients with severe depression and some brain surgeons want the procedure to be made more widely available.

Royal Melbourne Hospital neurosurgeon Associate Professor Richard Bittar says up to 75 per cent of patients with depression "seem to be obtaining a good benefit" from the surgery.

"My personal experience has been very similar to that - I've done five patients with depression and we've had good results there," he said.

The controversial procedure involves drilling holes into the skull and implanting electrodes into the brain.

The electrodes are attached to a battery pack that delivers electric pulses to stimulate or inhibit parts of the brain.

But Professor Bittar says the surgery is not available everywhere.

"New South Wales is the only state in the country which has outlawed surgery for mental illness, and what we're seeing is patients come down to Victoria to have their surgery, which is fairly unfair," he said.

"One of the other problems is when they go back home, in order to obtain the best benefit from their operation, they need to have some programming.

"And potentially if you interfere with the programming device you may actually be breaking the law."

Professor Bittar argues the ban in New South Wales should be overturned.

"A lot of it has to do with the older days of psychosurgery where people performing lobotomies, they weren't necessarily doing that in a very responsible matter," he said.

"So the lawmakers in New South Wales don't really seem to understand that surgery has changed.

"We now have more evidence to support what we're doing - we have psychosurgery review boards and other means by which we can evaluate patients and make sure that they're having surgery in appropriate circumstances."

Dennis Velakoulis from the Royal Australian and New Zealand College of Psychiatrists says there is no reason Australia cannot develop a nationally consistent approach.

"There are patients everywhere in Australia who may benefit from this treatment," he said.

"The issue will be about making sure that the treatment is undertaken in appropriate centres where there's the expertise and the critical mass.

"But I think there's no reason there shouldn't be a national policy that looks at this issue and allows people to access treatments that may help them with very severe illness."