Open this photo in gallery:

Ridings in Calgary will see major boundary changes if the province adopts a new electoral map.DAVE CHIDLEY/AFP/Getty Images

Alberta’s new proposed provincial electoral boundaries would result in major changes to ridings in Calgary and Lethbridge, expanding their footprints into more rural areas.

The chair of the independent panel that created the map dismissed concerns that the proposed boundaries, released publicly on Monday, would violate the Constitution. But Alberta NDP Leader Naheed Nenshi promised to file a legal challenge if Premier Danielle Smith’s government adopts the map, saying the new boundaries would hand an unfair advantage to Ms. Smith’s United Conservative Party.

He said the NDP cannot challenge the boundaries unless it’s first passed in the legislature.

“If the UCP has the nerve to pass this Trump-style, MAGA gerrymandered map, if they have the nerve to cheat to win … we’ll see them in court,” Mr. Nenshi said at a news conference after the report containing the map was tabled in the Alberta legislature.

Alberta NDP accuses Smith of gerrymandering as province prepares to unveil new electoral map

The proposed map has been the subject of intense debate and scrutiny since April when Ms. Smith rejected an independent commission’s proposed boundaries. Her decision fuelled accusations of gerrymandering, a U.S.-style tactic of manipulating electoral maps to create an artificial advantage.

After rejecting the first panel’s proposed map, Ms. Smith’s government formed a United Conservative Party-dominated committee that created a new independent panel charged with taking a second attempt at drawing the electoral map. It was chaired by retired Alberta judge Brian O’Ferrall, and included two members tapped by the NDP and two by the UCP.

The new report shows the five-person panel was sharply divided on how to proceed with the map, mirroring tensions among the previous group tasked with redrawing the provincial boundaries.

In the report, Mr. O’Ferrall writes that the panel’s “time and energy were taken up with responding to the indictments of the panel’s minority who suggest that the process of the advisory panel was constitutionally reckless, an abuse of process, and that the panel’s proposals infringed the Charter.”

The minority, made up of the two committee members named by the NDP – University of Alberta law professor Gerard Kennedy and former Okotoks, Alta. town councillor Brent Robinson – wrote in the report that several of the new recommended ridings would be “constitutionally fraught” and would likely be challenged in court.

Mr. O’Ferrall described the minority report as a “polemic passing judgement on the constitutionality of the panel’s process and its proposals which exceeds the panel’s mandate.”

It is unclear how long it will take for government to pass the new map if it decides to adopt it, but it’s expected to be approved before the fall session ends on Dec. 3.

Ms. Smith’s government has rejected calls to reverse course.

Alberta’s electoral boundary changes could reshape the political landscape. These maps show where

On Sunday, Alberta’s Justice Minister batted away Elections Alberta’s request for the provincial government to either not approve the new electoral maps or postpone next year’s general election to give the agency sufficient time to prepare for the 2027 vote.

The provincial government “has no intention” of shifting next year’s Oct. 18 fixed election date, Justice Minister Mickey Amery wrote in a statement.

Elections Alberta must prepare for the day “under the final electoral boundaries enacted by the Legislative Assembly,” he wrote.

Mr. Amery was responding to a letter from provincial chief electoral officer Gordon McClure, who on Friday circulated a letter to the province’s MLAs imploring them to reconsider implementing the new electoral boundaries.

Mr. McClure said Elections Alberta’s resources are strained and pursuing a different avenue would protect “the readiness and successful delivery of Alberta’s next provincial general election.”

He added the agency would need 12 to 18 months to implement the new map with 91 ridings, up from 87.

More to come