Canberra Health Services have said patients won't face delays as radiographers will take part in three weeks of industrial action.
Allied health workers from Canberra Hospital's medical imaging department, who are members of the Community and Public Sector Union, will not do any overtime for the next three weeks.
The action started on Friday morning.
The CPSU said the department was heavily reliant on staff doing overtime as they had to plug gaps due to retention and recruitment issues.
The union has been negotiating with Canberra Health Services over the past 18 months for a better pay deal and better conditions.
"If the government refuses to come to the table with significant improvements to the pay and conditions of allied health workers here in Canberra, they won't just be letting down these workers. They'll be letting down the thousands of Canberrans who rely on these local services every day," CPSU national president Brooke Muscat said.
Ms Muscat said workers were leaving the territory to take up higher paying jobs elsewhere.
"They are earning more money and working less hours," she said.
"The ACT government needs to step up to the plate and fight to keep our health professionals here in Canberra."
A Canberra Health Services spokesman said the organisation had worked with the CPSU and the staff involved to ensure the action did not affect the delivery of health services.
"All patient care will continue without delay," the spokesman said.
"Our radiographers are a valued part of team CHS. They do important work and provide a high standard of care to their patients."
Enterprise bargaining between the ACT government and health workers has been going on over the past year. This week, Health Minister Rachel Stephen-Smith said the government was working to finalise negotiations. She said the government was working to give health staff a generous wage increase.
Opposition health spokeswoman Leanne Castley attempted to get the government to agree to explore bonus payments for health staff this week but her motion was rejected by the Labor and Greens members of the Legislative Assembly.
Ms Stephen-Smith said health staff would be paid a one-off $1250 cost-of-living payment.
Radiation therapists have also taken part in industrial action over recent weeks, saying the government had failed to offer them a wage rise that was in line with other states.
The three-week overtime ban will finish on Saturday, November 18 at 11.59pm.
