Mayor Naheed Nenshi is strongly disputing former Alberta Health Services CEO Vickie Kaminski's account of government interference in relation to an ambulance dispatch plan for Calgary.

Kaminski stepped down from her position last November and, as CBC exclusively reported, alleged in her resignation letter that the newly elected NDP government interfered in a decision she described as having already been made to centralize emergency medical dispatch services.

But Nenshi, who has been a staunch opponent of the AHS plan to take dispatch out of the City of Calgary's hands, was dumbfounded by what she wrote.

"Nothing in Ms. Kaminski's letter relating to 911 or EMS bears any relationship to what I understood to be true," the mayor said.

Nenshi said he understood from both the previous PC government and the current NDP government that the decision had not been made.

In fact, Nenshi said former PC health minister Stephen Mandel came to Calgary to tell him in person how "horrified" he was by the AHS plan and that he was going to "put the entire thing on hold" pending a review of the 911 system in Alberta.

After the May 2015 election, Nenshi said he wrote to newly elected Health Minister Sarah Hoffman to express his understanding the dispatch change was "on ice and probably dead."

"Both minister Mandel and minister Hoffman affirmed multiple times that AHS had moved forward on this without approval from government," Nenshi said.

"So, Ms. Kaminski's account of it, written a few days before she announced that she had a new job somewhere, certainly bears no basis in the facts, as I know them."

Terse phone call

Nenshi said Hoffman assured him in writing last summer that Kaminski and deputy health minister Carl Amrhein would meet with him in person to address his concerns over centralized dispatch, chief among them that it would increase ambulance response times.

"Instead what I got was a phone call, which Ms. Kaminski started by saying: 'This is my decision. It's not up for debate, and I'm telling you what is happening,'" the mayor told CBC News.

Nenshi said Amrhein, who was on the call, "seemed very, very surprised with Ms. Kaminski's attitude and her tone."

The mayor said that was his third and final interaction with Kaminski during her entire tenure as CEO of AHS, all of which involved her trying to give direction to him.

"The first interaction was a letter that she sent me in which she forbade me from ever saying anything bad about AHS," Nenshi said.

"The second was a phone call in which I asked her why a civil servant should be telling an elected official whom she doesn't work for what he can and cannot say."

Nenshi said he never actually met Kaminski in person.

"It's interesting that she didn't feel it was important to talk to the mayor of her largest city," he said.

$6-million figure in dispute

The province revealed previously that an in-house dispatch centre had been built in Calgary so AHS could handle EMS calls separately from the city's 911 calls for police and fire.

The facility has come with a cost of about $60,000 in monthly rent since April 2015, although it is not in use.

In her resignation letter, Kaminski revealed further that AHS has leased the space for at least 20 years at an estimated cost of $750,000 a year and said a "large number of staff" had already been hired.

She also described her own job as CEO was redundant "if all AHS activities are going to be micromanaged by the government."

"The Minister of Health is now dealing directly with Mayor Nenshi and, in our latest meeting, informed me that AHS will not be moving this forward in the immediate future despite the costs the organization is incurring (unused staff and space) and the fact that continuing with the current service arrangement with the City of Calgary is costing $6 million more than it would cost if provided in-house," Kaminski wrote.

Nenshi, however said that was the first he heard of the $6-million figure, an estimate he also described as simply "not true."

"How could it be possibly be true when they're paying people at the same union scale and they're spending nearly $1 million a year on rent for a redundant facility that is not required?" the mayor said.

"The City of Calgary has said many, many times that we are willing to negotiate the costs and in fact, surprisingly, we were willing to provide about a $6 million discount," Nenshi added.

"So, even if that is true, we were willing to solve that."