An Australian researcher has reportedly developed a drug-free treatment for depression by combining brain training exercises with gentle brain stimulation.

Dr Rebecca Segrave is a neuropsychologist and researcher at the Monash Alfred Psychiatry Research Centre, who came up with the idea to combine gentle brain stimulation with brain training.

Dr Seagrave told Fairfax Media she was so shocked by the results of the trial she had to re-check her figures.

"It's really thrilling to sit with someone, one on one, and hear how their life has improved," she said.

The treatment combines computer-generated thinking activities with a gentle form of brain stimulation known as Transcranial Direct Current Stimulation (TDCS).

TDCS is a milder form of electroconvulsive therapy (ECT) which is also used to treat severe depression.

One participant had lived with depression since the age of 19, and over the space of 15 years had experienced lows without warning, or triggered by a stressful event.

After using various treatments, including medication and counselling, he enrolled in the three-week trial but did not notice a change in his mood during the 15 sessions.

"Then in June and July I had quite a few stressful situations and in the past I probably would've fallen into a heap," he said.

"However, I found I had this new resilience to get through them, which was really surprising."

In the pilot study involving around 30 participants, almost half of those who participated in the dual treatments improved, and about a third were in remission by the time they had their follow-up after three weeks.

"That means their symptoms of depression had gone completely," Dr Segrave said.

"People have gotten particularly excited about it because it's very safe, it's inexpensive and it's portable."