Professionals Australia ACT director Dale Beasley said hospital pharmacists were under immense pressure - with the department currently running on 50 per cent of the staff needed - due to poor pay and conditions.

The union wrote to Health Minister Meegan Fitzharris earlier this month saying that industrial action was on the table, warning it was only a matter of time before serious mistakes were made.

Mr Beasley said about half a dozen pharmacists were also looking to leave the hospital within the next few weeks.

He said the shortage was leading to mistakes being made that put patient health and safety at risk, with staff reporting times where the ratio of pharmacists at the hospital was 1 to 100 patients.

While there are no mandated ratios in the ACT, the union said industry recommended ratios were between one to 10 and one to 20 depending on the department.

"There's conflict in the workplace because pharmacists just can't provide the services that doctors and nurses need," Mr Beasley said.

"They want to be able to provide it but they just can't."

Mr Beasley said pharmacists often did not have time to adequately consult patients who were being discharged from hospital with complex health conditions, leading to re-admissions.

The union's analysis found ACT public pharmacists were up to $14,000 worse off than other jurisdictions.

While some pharmacists are offered relocation incentives, Mr Beasley said this was offered on an ad hoc basis.

“Hospital pharmacists are underpaid and not given the recognition they deserve and it means we’re bleeding staff to the Commonwealth and other jurisdictions every week," Mr Beasley said.

"Some members have even left with no job to go to at all, such is the stress they are operating under."

Mr Beasley said the crisis had reached crisis point with the government refusing to budge on measure that would help improve the attraction and retention of pharmacists.

"Members on the ground are at the end of their tether," he said.

"Our reps are really emotional because they just don't know where to go from here."

He said hospital pharmacists are responsible for compounding and dispensing medicines and advising doctors, nurses and patients on the proper use and adverse effects of medicines, and are critical to patient safety.

“We simply must improve attraction and retention of pharmacists to address workloads by providing a proper classification structure and an ongoing attraction and retention payment," he said.

“Canberrans deserve to know that when they go to hospital – whether its Canberra Hospital, Calvary Hospital or the new University of Canberra Hospital – they are going to get the right medications and the right doses."

Mr Beasely said the inaction by the government was reckless and the workforce was now considering rare industrial action.

“Unfortunately, this means the union has to consider next steps and while pharmacists are reticent to take industrial action given the impact on patients, it is definitely an option,” he said.

ACT Health has maintained its pharmacist salaries are competitive, saying it matches the NSW market rate.

"Through the enterprise bargaining process, ACT Health has committed to undertaking a review of the health professional structures, including pharmacists as a priority," a spokeswoman said.

"This is timely and as per the current health professional classification, will look at the relevant work level standards."

The spokeswoman said ACT Health was not aware of any increase in medication mistakes due to pharmacy staffing levels.

"Ensuring patients are sent home with appropriate information about medication is key part of the discharge process," she said.

"This function can be carried out by a pharmacist, a doctor or a nurse, as part of the patient’s treating team."

The spokeswoman said the proposed changes to the enterprise agreement will clarify the pay rates for pharmacists, ensuring the ACT is in a better position to attract and retain pharmacists.

"ACT Health is constantly looking at different workforce strategies to ensure we are in the best position to recruit and to attract and retain staff," she said.