Alberta's infrastructure minister says the province would take its $1.53 billion off the table if Calgary were to alter the agreed-upon plan for the first phase of the Green Line LRT expansion, as one candidate for mayor has been suggesting.

"We would have to take the project through our budget process all over again and there's no guarantee that the funding would be there, depending on what the process found," Brian Mason said Friday.

"And then that, of course, brings into question the federal funding as well."

Mayoral candidate Bill Smith told two Calgary newspapers on Thursday that he wants to pause and re-evaluate the $4.6-billion project and how to go about its first phase.

Rather than constructing expensive downtown infrastructure first and building truncated lines to the north and southeast, Smith said the first phase should involve a longer build-out in one direction or the other.

Pressed by reporters Friday about which direction he would build first — north or south — Smith said he didn't yet know.

"I guess my starting point would be, I guess, the number of people we can serve: Which is more bang for the buck? And I don't know that answer right now," he said.

"If I had a plan at this point in time, that'd be great."

Bill Smith told reporters Friday the city's plan for the Green Line "doesn't make sense to me." (Justin Pennell/CBC)

Incumbent mayoral candidate Naheed Nenshi held a press conference Friday to respond to Smith's position, calling it a "reckless" idea that would jeopardize funding commitments from higher levels of government.

"This is shocking," Nenshi said.

"And it really is remarkably, breathtakingly uninformed. It really shows Mr. Smith's habit of repeating what the last person he talked to said rather than actually answering — or asking — thoughtful questions."

The first phase of the Green Line, which would be the largest infrastructure project in Calgary's history, was approved by city council in June.

The project's costs are to be divided equally between the federal, provincial and municipal governments.

While the city and federal funds have been committed for some time, the province only agreed in July to put up its $1.53 billion, saying it wanted to see finalized plans before it would commit funding.

Smith believes 'province is committed'

Smith said Friday he doubts re-opening the project's plans at this point would jeopardize provincial funding.

"I can't imagine that suggesting that we want to make sure that we align with Calgarians' needs is going to be an issue," he said.

"I think the province is committed to seeing a line done."

But Mason said the province must evaluate specific projects when committing to provide such large amounts of money and can't offer generalized funding for a roughly defined plan.

"We're being asked to commit $1.5 billion and we don't do that just sort of because, oh, we love transit and want to help Calgary," he said.

"Those are true things but what is important is that we do our due diligence to make sure that it's a project that meets the criteria that we have set out for our funding."

'Just relax a little bit'

Nenshi was visibly agitated as he talked to reporters about what he described as the risks Smith's plan present.

"I worked hard for many years to secure the single largest investment from provincial and federal governments in Calgary's history in the Green Line — $3 billion — all of which is at risk," Nenshi said.

"The $3 billion was vetted on this project by the provincial and federal governments, and Mr. Smith is willing to throw that away."

"If someone wants to be a politician, they should do their homework," Nenshi added.

"This isn't fun and games. This is people's lives we're talking about."

Smith stood by his position, though, and suggested Nenshi was more agitated by a recent poll showing him in second place in the mayoral race.

"I would say, Naheed, it's just one poll and not to get too excited about where you are and just relax a little bit," Smith said.

Council voted 12-3 in favour of beginning the first phase of the project in the city's centre, where the most complex construction work needs to be done.

After evaluating several options for getting the new line past the Bow River and through the downtown core, council opted to go with an expensive tunnel option, burying the LRT tracks and several stations below ground.

The estimated cost of the tunnel beneath Crescent Heights, the Bow River and downtown is $2 billion, alone eating up nearly half of the available funding.

A rendering of what an underground station would look like as part of a tunnelled route for the new Green Line of the LRT system. (City of Calgary/Screenshot)

The city also opted for pricey options in order to get the line through the Beltline and into Inglewood and expects to be able to afford to build only about 20 kilometres of total line with the $4.6 billion in secured funding.

That would take the line from 16th Avenue in the north to the 126th Avenue in the southeast.

The original plan for the full Green Line was to build a 46-kilometre route stretching all the way from the city's northern periphery to the community of Seton in the deep southeast.

The city now plans to do that in phases, once funding beyond the initial $4.6 billion is secured.

Smith described the fact that the full line isn't going to be be built for $4.6 billion as a "boondoggle."