Premier Kathleen Wynne is reiterating her support for the one-stop Scarborough subway extension, despite rising cost estimates.

Toronto city staff had previously pegged the project, which will extend the Bloor-Danforth subway to Scarborough Town Centre, at $2 billion.

Earlier this month, it was confirmed that number had risen to $2.9 billion. And in a report going to the executive committee Tuesday, city staff estimate the cost to be nearly $3.2 billion.

But both Toronto Mayor John Tory and Wynne remained firmly in support of the extension when speaking with reporters after a meeting Monday morning.

"I have always deferred to city council in terms of the plans," said Wynne. "I will say, though, that the more often we change direction, the more often we scrap a plan and start all over again, the more expensive that is, and the more time it costs. So I'd like to see us move ahead in an expeditious way."

The changing cost estimates for the extension were the result of initial projections that were "not carefully thought through," Tory said.

"[Now] we're being honest with people and straightforward about what the cost is going to be."

The number of stops on the planned extension was reduced from three to one in January. Tory suggested reporters not get "fixated on the number of stops."

"What this is, is a significant extension of the Bloor-Danforth subway line into an under-served part of the city, that has been under-developed in terms of jobs and investment because it does not have adequate transit service," said Tory.

"It is an investment no one will question 25 years from now, because they will say this was the right thing to do."