Earlier this month the Calgary 2026 Bid Committee outlined their proposal for the Games, in which the above figure was put forward as the expected cost of hosting.

However, according to a report by the Canadian Broadcasting Corporation (CBC), a newly revealed council document suggests the real figure could well be higher, due to costs associated with the construction of an Athletes' Village.  

Last week's proposal published by the Bid Committee suggested a Village could be built on the site of the current Victoria Park transit centre.

However, for such a location to work bus barns would have to be moved to a new site where a modern facility would be constructed.

Meanwhile, any environmental contamination on the Victoria Park site would have be cleaned up.

According to CBC, potential costs associated with such construction are not included in the CAD$5.3 billion figure.

"The schedule and cost estimates may be impacted by complexities incurred while preparing the site for development," the leaked document reads.

The delivery of the Athletes' Village is identified in the council report as a key risk to the capital cost projections of the Games.

Commenting on the leak, advocacy group the Canadian Taxpayers Federation said whoever revealed the document deserves a reward.

"All costs need to be laid clearly on the table," their Alberta director Franco Terrazzano said in a statement.

"Calgarians have a right to know the total bill that will come with hosting the 2026 Olympics.

"Whoever this mysterious whistleblower is, they deserve a gold medal."

In response, Calgary Mayor Naheed Nenshi has said he will request a full investigation into how the document was leaked, while city manager Jeff Fielding has said he will direct corporate security to carry out their own investigation.

Councillor Peter Demong has been quoted as saying he was "deeply troubled" that the document was leaked.

"In the eight years that I've been here, I can count on my left hand the times we've seen a leaked document of this proportion," he said.

The Council reportedly discussed the issue at a meeting on Monday (September 24) evening. 

On November 13 the city will hold a referendum on whether to host the Games, with cost a primary concern of Olympic critics.

Calgary must win the vote for the bid to go ahead.

Other cities looking to host the 2026 Games include Stockholm in Sweden, Erzurum in Turkey and Milan and Cortina d'Ampezzo in Italy.