The new centre, which was officially opened on Thursday, was a $5 million refurbishment of the existing site and is the fourth addition of the ACT government's walk-in scheme.

ACT Health Minister Rachel-Stephen Smith said the new centre was designed to take the strain off Canberra's emergency departments.

"Canberra's walk-in centres provide people with access to health services closer to home," ACT Health Minister Rachel Stephen-Smith said.

"The walk-in centre will be able to treat people who have minor injuries and illnesses, including sprains and strains, every day of the year."

More than 17,000 Canberrans used the walk-in centres in Gungahhlin, Tuggeranong and Belconnen between July and September this year.

The opening of the walk-in centre comes days after the latest Australian Institute of Health and Welfare report showed the ACT had the worst median emergency department wait time in the country.

Fewer than half of people going through emergency in the 2018-19 financial year were seen on time.

Ms Stephen-Smith said the walk-in centre was one of a range of measures to cut down on emergency waiting times.

"We're doing everything we can to take pressure off emergency rooms and improve waiting times," she said.

"What we have seen is that the overall number of people at the emergency department has increased, but the number of presentations in category four and five, the lower acuity presentations reduced by 10 per cent."

The nurse-led centre would employ more than 10 full-time equivalent nursing positions and four time full-time equivalent administration staff.

Walk-in centre clinical nurse manager Kirsty Cummin said some staff at the Weston Creek centre had been drawn from other walk-in centres across the ACT.

"We've been doing an onboarding of staff over the last few months, and with the three existing centres we've been able to remix our teams and have a mix of experience of staff," she said.

The new centre will operate alongside a community health centre, which had been closed since January to allow for construction of the walk-in centre.

Ms Stephen-Smith said the centre would be able to accommodate for the area's growing population as people move into new suburbs in the Molonglo area.

A second stage of the Weston Creek medical walk-in centre is slated for completion in early 2020. Stage two would provide additional space for maternal and child services.

The ACT was the first jurisdiction to adopt this form of healthcare and the first walk-in centre opened in 2010.

A fifth site in Dickson is under construction and is planned to be opened in late 2020.