Men over the age of 85 are more likely to die by suicide than Australians of any other age group, according to data from the Australian Bureau of Statistics.

The suicide rate for men aged 85 and older was 37.6 per 100,000 in 2012, more than triple the national rate.

The figures were released on Monday in the Australian Bureau of Statistics' causes of death data.

The director of old age psychiatry at St Vincent's Hospital in Sydney, David Burke, said the main cause is depression.

"We think that probably around 90 per cent of people who attempt suicide or complete suicide have been depressed in the time leading up until that event," he told RN Breakfast.

"There's a number of factors that lead to depression in old age.

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"The biggest one is probably loss ... through bereavement. People often lose their spouse and lose their friends.

"It has to do with loss of roles sometimes, with people retiring and not finding a new level of functioning in the community.

"It has to do with issues like social isolation and it's also often related in old age to physical illness.

"So people with acute and with chronic physical illnesses can often become depressed in association with that."

Australian Bureau of Statistics: Causes of Death, Australia, 2012

Age-appropriate mental health services needed: psychiatrist

Across all ages, there were 2,535 suicides in 2012, making it the 14th leading cause of all deaths.

Three quarters of people who died by suicide were male.

"Most older people are functioning at a very high level and, in terms of their mood, they are not depressed at all," Dr Burke said.

Sorry, this audio has expired ABS: Older male Australians most likely to suicide

"A significant number do become depressed - we think somewhere between 10 and 20 per cent of people in old age suffer from depression at some time after the age of about 60 or 65."

Dr Burke said general practitioners have increased their awareness about depression in old age but more could be done.

He said access to age-appropriate mental health services could be improved.

"The two main issues we deal with in terms of older peoples' mental heath are depression and dementia," he said.

"The treatments aren't radically different but I think that the older population can present differently with depression compared to younger people.

"I think sometimes the way in which medication and cognitive behaviour therapy can be used in older age needs to be particularly well understood by health professionals involved.

"I think there is a demonstrated need for specialised older age psychiatry services."