The contract between the ACT government and Canberra-based health services firm Aspen Medical for the pop-up emergency department was officially signed on April 24.

This was two weeks after the project had started construction on Garran Oval and more than a month after the government had entered discussions with Aspen Medical.

Health Minister Rachel Stephen-Smith, along with health officials including chief health officer Dr Kerryn Coleman, appeared before the ACT Legislative Select Committee on the COVID-19 Pandemic Response on Friday.

Opposition health spokeswoman Vicki Dunne asked the Health Minister if the timing of the contract passed the pub test given discussions with Aspen Medical began in late March.

"Maybe at the time the decision was made that we needed to go to Aspen we would need surge capacity... currently we don't need surge capacity, has there been any thinking between the March 22 and April 24 when the contract was signed whether or not we needed to go ahead with this," Ms Dunne asked.

"When the decision was taken [for the ED] we were entering into good faith discussions with Aspen Medical," Ms Stephen-Smith replied.

"[There was a] high level of uncertainty about what the course of the pandemic was going to be in Australia and there still is to be honest."

Chief Minister Andrew Barr was also asked about the emergency department in a separate hearing later in the day.

Committee chair and Opposition Leader Alistair Coe pushed the Chief Minister on whether the pop-up ED was directed by the national cabinet.

Mr Barr replied all states and territories were asked to increase capacity but the direction to build the department was not a request from the Commonwealth.

"Decisions as to how that would be undertaken are taken at a state and territory level," he said.

Ms Dunne also pressed the Chief Minister on why he did not tell an earlier committee hearing on April 17 the contract had not been signed when asked.

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It came as the ACT has no active COVID-19 cases and Ms Stephen-Smith acknowledged the pop-up department may not be used.

"It was clearly intended to be an emergency department facility, so that's what the design has been towards," she said.

"With no active cases it's looking like we may not need that emergency department surge capacity.

"This situation may change, I think it's really important to recognise that while we are in a really good position there is still a virus out there in the world, a virus out there in Australia.

"We have seen how quickly cases can start to multiply once you do start getting a few clusters in the community."

The facility could only be used for coronavirus purposes and Ms Stephen-Smith said discussions were underway as to what to do if treatment of patients was not required.

"We have been clear this is a COVID facility and it will only be used for COVID purposes," she said.

"We are working through now whether we use that facility for some simulation work, whether we use that facility for some other COVID-related activity or whether we essentially keep it there available for an emergency department surge facility whether it should be required at some point during winter for COVID patients."

The department is tied to the government's 90-day public health emergency declaration, currently in place until July.

If the declaration was not extended at this point the facility would have to be demobilsed.

About 90 per cent of it can be reused and the territory owns the building at the end of it.

Dr Coleman also addressed the committee on testing rates. She said since criteria was expanded last Friday to include anybody with symptoms between 170 and 280 people had presented for testing each day.

The ACT chief health officer also said she was confident the number of asymptomatic cases in the territory was low and that such cases would not contribute to transmission.

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