The figures, boosted by a March crackdown on smokers, came as staff unions backed the move to an entirely smoke-free campus from September.

Health Services Union organiser Bev Turello said she had noticed a recent increase in the number of butts around the front of the campus, which she attributed to a lack of direction. ''We need better signage. It says smoke-free campus, but there's no signs telling them to go to a designated area,'' Ms Turello said.

ACT Health figures for March show security guards spoke to 592 visitors or staff who smoked outside the hospital's two designated smoking areas, up from a monthly average of about 120.

One regular visitor said he had observed brazen smokers light up in front of no-smoking signs.

''I found it infuriating when escorting my [85-year-old] mother to and from hospital after a heart attack, and then for a pacemaker, and having smokers all round, daring me to say something and blowing smoke all round among no-smoking signs,'' the man said.

An ACT Health spokesman said the prohibition of smoking from hospital grounds was a constant challenge, but staff who ignored the smoke-free policy could be subject to disciplinary action under their employment contracts.

''ACT Health security guards are required to be vigilant in their monitoring of smokers who are non-compliant, particularly at the entrances to Canberra Hospital, but do not issue fines or penalties for smoking violations,'' the spokesman said.

Ms Turello said the HSU had not received any complaints about the move to shut the staff smoking zone, set up after the campus became smoke-free in May 2009, despite an estimated 100 workers using the area each day.

''I would expect there would be this offer from ACT Health to help their workers who have this addiction - provision of nicotine replacement for a certain period of time, and access to Quit information.''

The Australian Nursing and Midwifery Federation has also backed the total ban, saying it would further ensure environmental smoke was avoided.

Nicotine-dependent smokers who are inpatients at the hospital will continue to be provided with free nicotine replacement therapy, including patches or gum.