Premier Kathleen Wynne faced questions in the legislature Thursday about her government's intention to extend Toronto's subway system further into Scarborough, with a key opponent suggesting the Liberals aren't up to the job.

At the start of Thursday’s question period, Progressive Conservative Leader Tim Hudak pressed the premier as to whether her government could be counted on to build the subway.

"The Liberals may talk a good game. They may talk about subway stops, they may announce subway stops," Hudak said.

"Speaker, after 10 years of Liberal government, additional Liberal subway stops? Zero."

The PC leader asked the premier if the government remained committed to extending the Bloor-Danforth subway further into Scarborough.

"We have committed that we have $1.4 billion, plus another $320 million, that we commit to building a subway in Scarborough," Wynne said.

"That commitment is on the table, we will move forward with that," the premier said, adding that the Progressive Conservatives had not been supportive of building transit.

In response, Hudak asserted it was the PCs who had been responsible for building the backbone of Toronto’s existing subway system over the decades.

Citing the achievements of governments led by past premiers Leslie Frost, John Robarts, Bill Davis and Mike Harris, Hudak put some provocative math forward about the Liberals’ long-term record on subway building.

"The number of subway stops the Liberals have built in Toronto? Zero," he said, with his fellow caucus members yelling out the number in unison.

"The number the PCs have built? Sixty-four."

A few minutes later, Transportation Minister Glen Murray suggested that the current era Progressive Conservatives could not claim any successes on transit.

"I'm waiting for them to go back to John A. Macdonald and the railroad," he said in the legislature.

"But the reality is these new Tories haven’t built a subway. That group never, ever laid a line -- that group, Mr. Speaker, only filled them in."

Stintz not sold on Murray's subway plan

The transit-related exchange in the legislature came a day after Wynne met privately with TTC chair Karen Stintz.

Stintz has voiced concerns about a proposal recently announced by Murray to extend the subway to Scarborough Town Centre, but not up to Sheppard Avenue, as Toronto City Council wants to do.

"We want to build the right service for Scarborough," Stintz told CBC News. "This isn't a subway; it's an elevated two-stop route."

The city had an agreement to build a seven-stop light-rail line running from Kennedy Station all the way to Sheppard. That project was fully covered by provincial money but this summer the city opted for the more expensive — and not fully funded — subway option.

That prompted Murray to propose the shorter subway extension last week.

Stintz said the Murray plan doesn't account for all the costs of switching from light rail to subway, including subway cars and signal systems.

"Those elements are quite costly and it's unclear whether the city is expected to pick up the cost," she said.

She also said there are technical problems associated with the subway plan, including:

Kennedy Station would have to be moved to accommodate subway cars, which could affect the Eglinton-Crosstown line already under construction.

Running subways along the light rail route will require tight turns, forcing subway trains to slow down.

The Scarborough RT won’t be able to continnue running during the construction period, anywhere from three to five years. This will mean using shuttle buses along the route.

Toronto Mayor Rob Ford is also concerned the city will be on the hook for $85 million in so-called sunk costs of switching to subway technology.

For the Murray plan to go ahead, the current master agreement between the city and Metrolinx — the province’s regional planning body — would have to be revisited by Toronto city council.

"Glen Murray said he was going to pay for the subway overruns, now Metrolinx is saying we're responsible for it," said Ford.