Level 4 in building 1 was vacated by paediatrics in December 2013, with the completion of stage 2 of the Centenary Hospital for Women and Children, and it was renovated between April last year and February at a cost of about $9 million.

A number of levels in the building have been extensively refurbished as part of major works on the southside hospital campus.

But six months on and no decision has been publicly made about what level 4 will be used for - a "simply unacceptable" situation, according to Opposition Leader Jeremy Hanson.

"We know we have a critical shortage of beds which at times has led to dangerous levels of bed occupancy," he said.

"It sounds chaotic that there would be an entire floor vacant with no clue what they're going to do with it. It's just extraordinarily bad planning. This is a government fixated on a tram at the expense of our health system."

Access to level 4 was also blocked off during construction works for the refurbishment of the level above, an ACT Health spokeswoman said.

Demolition works to remove old wards and prepare for the renovations started in September 2014, before the level 4 refurbishments began in April 2015.

Health Minister Simon Corbell insisted it was incorrect to say the level had been sitting empty the entire time.

"It would not be accurate to say the floor has been vacant because that would suggest there's been nothing happening in it. Clearly the floor cannot be used when demolition and refurbishment work is underway," he said.

Mr Corbell maintained renovations on level 4 had not increased bed pressure in other parts of the hospital.

"The beds that were closed for the refurbishment were replaced by the new Centenary Hospital for Women and Children and that facility is actually an expansion in the total capability in that part of the hospital," he said.

Asked about the length of the renovations, Mr Corbell said: "when you're undertaking refurbishment work in an existing operational facility, you are much more constrained in what you can do".

"You've got to remember there are operational floors above and below this floor and obviously it's a much more complex task to demolish old infrastructure and refurbish with modern refurbishments, so no, it's a quite standard timeframe," he said.

A spokeswoman said ACT Health was considering the future use of level 4 "in the context of changing demand" for services currently occupying building 1, which includes coronary care, orthopaedics, the stroke unit, gastroenterology and general surgery.

ACT Health was doing a comprehensive analysis, looking at the distribution of services across the ACT to project future demand on service.

"The use of level 4 will be determined in the context of this analysis and the most appropriate use of space across the hospital campus to meet future service needs," she said.

The ACT has one of the country's most expensive public hospital systems, which Mr Corbell blamed on existing infrastructure not being used efficiently.

"The government's focus has been on improving utilisation, particularly bed utilisation, so more people get access to more beds using the existing infrastructure," he said.

"Otherwise we're just adding more and more beds that is pushing up the cost of public hospital services when we could be achieving more with the same amount of money that we're currently spending."

He said the government was focussed on providing more efficient and timely access to public hospital services in the ACT and they would deliver a "net gain" of 50 extra beds through "better bed utilisation and better utilisation of existing bed stock".

"It's not about compromising care, but it's about making you sure you have timely discharge arrangements," he said.