It comes after The Canberra Times earlier this year revealed planning work on the new Surgical Procedures, Interventional Radiology and Emergency centre (SPIRE) had hit a speed bump due to the planned location of the hospital expansion on a site with a helipad and car park.

Health Minister Meegan Fitzharris will today announce the expansion will be built on the north-eastern side of the hospital campus between Hospital Road and Palmer Street, with construction to start in 2020.

She said the new site - to be built on mainly administrative buildings - would mean minimal disruption to critical care services during construction.

It was previously to be built on the site of the helipad and connected to building 12.

"It will replace administrative buildings that are aged while allowing integration with other acute services buildings on the campus," Ms Fitzharris said.

The expected opening of the 2016 flagship election promise has already been pushed back to 2024, after it was originally planned to be open by 2022.

Construction is due to start in 2020.

The expansion will boost the number of operating theatres from 13 to 20, and add another emergency department to the hospital.

It would include two inpatient wards with 64 beds, new critical care and imaging facilities, a 24-bed high-level coronary care unit and a 48-bed intensive care unit.

Documents previously obtained by The Canberra Times said there had been "logistical challenges" at the original proposed site for the new section of the hospital.

"In particular, the immediate works required to replace the helicopter landing site and 350 car parks, which unlock the site for SPIRE construction to commence, is a challenge to both the delivery time frames and costs of the project," the documents said.

"The next design phase of the project will include an infrastructure master plan which will investigate alternate site options."

Ms Fitzharris said the new site was decided in collaboration with health services providers and key stakeholders.

"ACT Health has already kicked off engagement with our clinical workforce on this important project and I look forward to these discussions and more detailed conversations continuing in 2019 as early design work progresses with clinicians and other stakeholders," she said.

Ms Fitzharris said ACT Health was also working closely with Calvary Public Hospital to explore an expansion of health services and infrastructure in Canberra’s north.

“As part of the whole-of-territory approach to health services and infrastructure planning, we are undertaking a northside hospital services scoping study, which will explore health service and infrastructure options across Canberra’s north," she said.

“We know Canberra’s north is rapidly growing, so to future-proof our healthcare system we are looking at how we can better deliver health services so Canberrans receive high quality healthcare where and when they need it.”