Upgrade of ailing hospital assets are behind schedule and over budget

The government is also behind schedule in its bid to fix a raft of other building risks identified at the hospital, with most projects overdue.

The original cost to replace the ageing electrical main switch board was $14 million, but the expected cost is now $42 million.

As of January this year, $18.7 million had already been spent on the project.

The original expected completion date was September 2018, but the latest prediction is December this year.

The switchboard caught on fire in April 2017, but the government had known it was at "extreme risk" of failure more than a year before the fire.

A contract to replace the switchboard was awarded just days after the fire.

The budget figures were disclosed in response to questions taken on notice in the ACT Parliament.

The projects are part of the government's plan to upgrade and maintain ailing assets in ACT Health, in part informed by a report handed to the government in 2016 by engineering firm AECOM.

That report revealed four extreme risks and 143 high risks in Canberra Hospital's infrastructure.

The government's upgrade plan is grouped into 16 projects, which include the heating and ventilation and air conditioning; hydraulics; electrical switchboard; and lift upgrades.

Just four projects have so far been completed. Of the 12 remaining projects, only two are on track to be completed on time.

The upgrade of the hydraulics system has faced the longest time blow out, with its expected completion date jumping from December 2017 to July 2020.

In answers to the questions asked by Opposition health spokeswoman Vicki Dunne, ACT Health put the cost and time blowout in replacing the switchboard down to a change in scope of the project.

It said the scope and costs "evolved" to reflect the realities of the complex project "and its impact on critical buildings across the Canberra Hospital campus".

Among the events which contributed to the blowout was the fire remediation and "implementation of lessons learnt from this fire event".

Mrs Dunne will on Wednesday move a motion in ACT Parliament calling on the government to make its plans for the renewal of the city's ageing health infrastructure public.

"Expenditure on infrastructure is absolutely vital and is now absolutely out of control because the government has neglected it for so many years," she said.

"These are infrastructure risks that the government has known and been warned about for years, but has failed to address.

"Canberrans are now faced with monumental cost blowouts thanks to the incompetent management of critical hospital infrastructure by successive Labor."