The city-provincial dispute over rapid-transit funding has reached the stage where Main Street is threatening Broadway with legal action.

Mayor Brian Bowman said Wednesday the City of Winnipeg has sent the Province of Manitoba a demand letter warning of potential legal action if Brian Pallister's Progressive Conservative government does not provide nearly $8 million worth of funding promised for the Southwest Transitway.

The mayor said the city is seeking about $8 million from the province as part of a deal the Pallister government signed to complete the city's first bus corridor and widen Pembina Highway at the Jubilee Avenue underpass.

"If you can't trust a written legal agreement a government signs, it brings into question the relationship," Bowman said Wednesday at city hall, following an executive policy committee meeting.

Mayor Brian Bowman said Wednesday the City of Winnipeg has sent the Province of Manitoba a demand letter warning of potential legal action if Brian Pallister's Progressive Conservative government does not provide nearly $8 million worth of funding promised for the Southwest Transitway. 1:30

Bowman first disclosed the dispute in February, when he said the province was trying to amend a deal to extend the Southwest Transitway from Jubilee Avenue to the University of Manitoba's Fort Garry campus and widen Pembina Highway below Jubilee Avenue.

The city and province each agreed to cover $225 million of the tab when the total project cost was estimated to be $587 million. Ottawa agreed to pay for the rest of the project.

The project cost was then reduced to $467 million after the city's private construction partner, a consortium called Plenary Roads, came up with a more detailed design.

The project is underway and is slated to be finished in 2020.

In February, PC government spokesperson Caitlin MacGregor said the city was trying to get paid for contingency funds — and those are not eligible for funding under a federal program that pays for public-private partnerships, such as the transitway deal.

She said the province's desire to amend the deal stemmed solely from the change in project cost from $587 million to $467 million.

In May, the city pegged the shortfall from the province at $8.7 million. Bowman said Wednesday the demand letter was sent due to the serious nature of what he described as the province's unwillingness to respect a legal contract.

An artist's conception showing part of the second phase of the Southwest Transitway, including the new crossing at Jubilee Avenue and a widened Pembina Highway. (City of Winnipeg and Plenary Roads Winnipeg)

At the Manitoba Legislative Building, Municipal Relations Minister Jeff Wharton said the disputed figure is now $7.9 million.

Wharton dimissed Bowman's complaints as "election-year politics," and said officials from both governments are working to resolve the dispute.

Mayoral candidate Jenny Moktaluk criticized Bowman's rhetoric.

"Suing the provincial government, who is our partner, is just one more example of this administration's adversarial approach to almost every problem that we have," she said at city hall on Wednesday.

Asked how she would improve city-provincial relations to Winnipeg's satisfaction — a task that has eluded every mayor since Stephen Juba was elected in 1956 — Motkaluk suggested she is different.

"I don't have the objective of simply prying more money out of Broadway," she said.