Centralizing dispatch for emergency medical services could cause a "massive increase" in a lack of ambulances to dispatch to 911 calls in Calgary, according to the Wildrose Party.

The province built a dispatch centre in Calgary to handle EMS calls separately from police and fire and is paying $60,000 in monthly rent since last April, although it's not in use yet.

Calgary Mayor Naheed Nenshi slammed the plan in December saying it would increase response times leading to lower patient outcomes.

Health Minister Sarah Hoffman says she is going to take the time needed to make the best decision for Albertans when it comes to a program the previous government launched.

But Wildrose health critic Drew Barnes said there is already a disparity between the service Calgarians and Edmontonians received last year.

In the first 11 months of 2015, Edmonton had 888 code red events — that's when there is no ambulance available to dispatch.

Calgary, in the period had only 39, the Wildrose says.

"The health minister's continued waffling on this issue is only causing undue stress in the Calgary health community, and is sticking taxpayers with a $60,000 a month bill to pay the rent on an empty AHS facility," Barnes said.

In question period, Minister Hoffman shot back.

"We have about 500,000 calls every year," she said.

"Decades of mismanagement by the previous government undermined the hardworking, dedicated staff and the Official Opposition plan to cut billions of dollars from public health care would only lead to longer wait times."

She said the government is working with municipalities and other agencies to arrive at a solution that works best for everyone.

"I will tell you what is not credible," the minister said.

"Making allegations that you are somehow going to improve health care when you are proposing to cut billions of dollars from the provincial treasury — that is ludicrous."