A defamation lawsuit against Calgary's mayor is set to go to trial early next year.

Mayor Naheed Nenshi is being sued for remarks he made about homebuilder Cal Wenzel during the last municipal election campaign.

Negotiations between the two sides have failed to resolve the matter, so a 14-day trial has been set down for February, 2016.

Nenshi made comments on CBC Radio about Wenzel, the founder of Shane Homes, during the 2013 election campaign.

Wenzel says the remarks — which insinuated he broke election laws and runs a mafia-like organization — were untrue.

He is suing Nenshi for $6 million in damages.

Nenshi's chief of staff, Chima Nkemdirim, says it's disappointing an out-of -court resolution has not been reached.

"It's unfortunate. We were hoping that this matter would be resolved by now," he said.

"You know the mayor has tried to resolve this matter and continues to remain hopeful that it can be resolved before it goes to trial."

Nenshi is covering his own legal costs.

But politicial scientist Duane Bratt says a 14-day trial raises questions about whether Nenshi must take a leave of absence during it.

"If he wins, I don't think that necessarily vindicates him. It has been quite costly to go through this and if he loses, that's going to be incredibly damaging to him."

Earlier this year, a judge granted Nenshi's request for a civil jury trial in the case.