The major revamp will see about 300 new beds overall, bringing bed numbers to 1500, and 107 extra staff at the Centenary Hospital for Women and Children.

Labor's first announcement of the official election campaign, which begins on Friday, is a counter to the Liberals' promise in August to build a $395 million hospital building, a promise enthusiastically welcomed by health professionals but dismissed by Labor in August as spendthrift and unnecessary.

Now, Chief Minster Andrew Barr has announced his own new hospital building. Dubbed the Surgical Procedures, Interventional Radiology and Emergency Centre, or SPIRE for short, it would be sited at the Kitchener Street end of the hospital campus and open "around 2022".

It would expand the number of operating theatres from 13 to 20, and have separate theatres decided to emergency and elective surgery so elective surgery is not delayed by emergencies.

It would include two inpatient wards with 64 beds, new critical care and imaging facilities, a 24-bed high-level coronary care unit, a 48-bed intensive care unit, including for paediatric care, and a new day surgery centre with seven surgery rooms.

Aspects of Labor's announcement are similar to the Liberals', which also promised a new emergency department, medical imaging, space for 20 operating theatres and a 48-bed intensive care unit.

Mr Barr dismissed the Liberals' plan as five years' old, given it was based on work done by Labor in 2014. In contrast, the SPIRE Centre and expanded women's and children's hospital would "reflect best practice in modern hospital design and delivery".

A new emergency department would be built next to the SPIRE Centre, allowing the existing emergency department to be dedicated to women and children. The two emergency departments would operate as one, but have separate entrances. The SPIRE and emergency buildings would cost $500 million.

Labor's plans for the women and children's hospital would cost another $150 million, a mix of capital and staff spending, with 107 new staff, half of whom would be nurses.

It would include a 12-bed child and adolescent mental health unit, an adolescent gynaecology service to reduce the need for young women and girls to travel to Sydney for treatment, 12 new paediatric high-dependency units and four paediatric intensive care beds.

Labor has not made a commitment for extra staff in the SPIRE Centre, with the 1200 staff employed there to come from existing ranks and expansion already planned in the budget.

College of Surgeons chairman ACT Sivakumar Gananadha welcomed the announcement, as "a great move forward" and "very positive".

"I' m really happy that the focus is now on health rather than light rail, that's the main thing that we would support," he said.

The biggest issue facing surgeons was getting access to theatre time, with a long list of patients waiting for elective surgery, so the expansion to 20 operating theatres and the new day surgery unit were welcome.

As to the difference between the Labor and Liberal promises, he said the college would support both plans because they both tackled the problems in surgery.

Darlene Cox from the Health Care Consumers Association said the Labor promise seemed to be a more comprehensive approach at the hospital, with the standouts including the much-needed adolescent mental health unit, the day surgery unit and the expanded, and the bigger intensive care unit. The appeal of the Liberal plans so far was the announcement of new local public hospitals for Gungahlin and Tuggeranong,

Labor took a promise for a new hospital to the last election, but the project was put on hold in 2013 for budget reasons.

Four weeks ago, the Liberals announced they would build the hospital for which Labor did detailed design work in 2014, and medical professionals urged Labor to follow the Liberals' lead. But deputy Chief Minister Simon Corbell pooh-poohed the plan, accusing the Liberals of spending money on infrastructure whereas Labor was concentrating on making existing beds work more efficiently. Mr Corbell said then that the government had a plan to upgrade the hospital in five to 10 years.