The University of Canberra Hospital is due to open in the middle of this year with staffing and budgeting still being finalised.

Unions met with ACT Health last week when they were told staff - including wards persons, hospital assistants, maintenance workers, caterers, security, administration and cleaners - would be filled through a contractor.

While Canberra Hospital makes use of contractors for some non clinical roles - such as security and cleaning - the use of contractors for wards persons, hospital assistants, catering and daily maintenance is new.

The move to dramatically expand the use of contractors to fill health roles has alarmed unions.

United Voice secretary Lyndal Ryan said direct government employment almost always led to better services and better conditions for workers.

She said she was surprised and disappointed the government had moved further towards a public and private partnership at the hospital.

"Health services just should not be privatised," Ms Ryan said.

"We have just had a six year battle to lift wages for cleaning staff at Canberra Hospital who are contractors so you can understand the difficulties that contracting poses.

"We are very concerned about the contracting out of services at the hospital.

"But we are a union that has an enormous amount of experience in doing these things so we are confident we will deal with whatever is thrown our way."

She said she was concerned Medirest - one of the contractors engaged by ACT health - had been employing staff at Calvary under the wrong award.

Health Services Union NSW/ACT secretary Gerard Hayes said they would be seeking an urgent meeting with Health Minister Meegan Fitzharris over the revelations.

He said in HSU's experiences with healthcare contractors quality of service and workplace conditions were often compromised in order to make profits.

Mr Hayes said there was a significant chance its workers - which include hospital assistants, caterers and wards people - would be paid less than those working at Canberra Hospital on awards it fought for.

"What is even more concerning is that the company involved has been awarded a 25-year contract and has a dubious record on workplace issues," Mr Hayes said.

"We are also a little uncertain why you would create a divide under three hospitals."

A spokeswoman for the government said ACT Health was currently engaging and consulting with staff, unions and other staff representative organisations about the hospital's staffing details.

"In regards to the procurement model for the new University of Canberra Hospital , in 2014 the Government made the decision to use a Design Construct and Maintain contracting model," she said.

"The proposed Model of Service Delivery for the new hospital, which was out for public consultation in 2014, included the DCM approach to provision of non-clinical services.

"The contractor was engaged in 2015."

The consultation document did not specify what services - except for cleaners and security - would be contracted out.

Instead it said management services and soft services could be contracted out.

"As we establish the services at UCH, we are committed to engaging with staff and their representatives and look forward to the ongoing conversations," the spokeswoman said.

At full capacity it will have 140 overnight inpatient beds, 75 day places and additional outpatient services and 300 staff.

Construction on the hospital - a specialist rehabilitation, recovery and research facility - finished last month and it is due to open in the middle of this year.

It will physical and mental health services by referral, including tailored inpatient and outpatient programs.

It will also be a research and training facility, providing students with work-integrated learning opportunities and educational spaces.