Recent data out of the Productivity Commission shows that the industry, which is already under strain, relies heavily on staff aged over 55, raising questions about the future of mental health services once they retire.

Of the 45 psychiatrists employed in the territory as of 2016, about 47 per cent had been 55 or older and over-65s accounted for 21 per cent. Under-35s represented about 5 per cent, or 2.25 people, in the workforce.

Mental health nursing had about 37 per cent of staff older than 55, while about 19 per cent had been younger than 35. Psychologists had the highest proportion of younger workers of a total 614 employed, with about 22 per cent under the age of 35. About 26 per cent of the workforce was older than 55.

"We know if we don't do something about it by 2030, we'll be 19,000 mental health nurses short across the country," Australian College of Mental Health Nurses chief executive Kim Ryan said.

"We've been talking about the aged workforce for quite a long time and not just in the ACT."

The ageing trend, which the ACT government agrees is concerning, is not unique to the territory, with data indicating a similar issue across most of Australia.

The best way to encourage younger people to pursue the work was to rectify the industry's "image issue" and ensure staff had adequate support, Ms Ryan said.

"We've seen lots of reports across the whole country, particularly over the end of last year around the level of abuse in the health care industry," Ms Ryan said.

Australian Salaried Medical Officers' Federation's ACT branch executive officer Steve Ross said responsibility for mental health services ultimately rested with officials.

"By making and ensuring Canberra Health Services is an attractive place to work and that there's support, training and sensible decision making, that goes a long way to addressing future issues in terms of ageing workforce and the like," Mr Ross said.

Canberra Health Service's mental health staff were trained in managing violence and encouraged to report any incidents, an ACT Health spokeswoman said.

"Canberra Health Services CEO Bernadette McDonald ... has established and is chairing a working group to develop strategies to address occupational violence in all its forms," she said.

"While we can never fully remove the risk, we take this issue very seriously and recognise the need to continually review our policies and procedures."

Universities Australia data shows 898 people graduated from clinical psychology degrees in 2017, compared with 879 people in 2016 and 931 people in 2015.

The Australian National University, the University of Canberra and the Australian Catholic University could not provide specific data on their courses.

A Canberra Health Services spokeswoman said it ran recruitment campaigns and worked with recruitment companies to encourage young people in the ACT to join the mental health workforce.

A workforce development committee had been convened, and timeframes for hiring mental health professionals could vary from 12 to 18 months for overseas applicants and three to six weeks for interstate applicants.

Local applicants could often start work within six to eight weeks.

"All vacant medical positions are advertised through the ACT [public service] jobs website and other relevant sites," the spokeswoman said.

Current mental health staffing was inadequate for the size of the territory's population, Royal Australian and New Zealand College of Psychiatrists ACT branch chair Jeffrey Looi said.

The lengthy academic and qualification processes involved in becoming a psychiatrist explained the low proportion of those staff under 35.