Ontario's governing Liberals now say they are open to the possibility of helping to extend the subway in east-end Toronto, as a number of city councillors turn up the heat on the issue.

Transportation Minister Glen Murray said Thursday that he is personally "not fussed" as to whether Toronto replaces its aging Scarborough RT with a light-rail system or with a subway.

At present, Metrolinx, a provincial transportation agency, is poised to build light-rail along the existing Scarborough RT, which is coming to the end of its lifespan and must be replaced.

But as the political pressure intensifies to extend the subway in Scarborough instead of a light-rail system, the province is backing away from its prior resistance to the idea.

The additional costs of going with a subway over light-rail are estimated by the TTC to be at least $500 million — perhaps closer to a $1 billion, if estimates from the provincial planning agency Metrolinx are to be believed.

On Thursday, Murray denied reports that the province has been negotiating with the city on the subway issue.

The minister said he’s waiting to see what Toronto councillors decide on July 16, at which point they could decide they want to see a subway built in Scarborough, instead of the existing light-rail plan.

Murray said that if council wants a subway, he'll discuss the matter with them. But he said that the province will have the final say.

Toronto Mayor Rob Ford has long pushed for the city to expand its subway network, including in Scarborough.

When hosting a recent barbecue in Scarborough, Ford reiterated his intent to bring a subway to the area.

"Mark my words, these subways are coming," the mayor said.

Ford has asked the city manager, Joe Pennachetti, to deliver a special report to council at the July 16 meeting, which will lay out options Toronto could consider to build a subway.

Coun. James Pasternak wondered aloud on Twitter if the council meeting would "define" next year’s municipal election.

The question of whether to build a subway is also shaping up to be a key issue in an upcoming provincial byelection in Scarborough-Guildwood, which will take place on Aug. 1, along with four others across Ontario.

On Thursday, Coun. Gary Crawford tweeted that when candidates come knocking at the door this month, residents should be asking them pointed questions about subways:

Ontario's Progressive Conservative Party has accused the Liberals of changing their position on the Scarborough subway issue in a bid to woo Scarborough voters.

With files from The Canadian Press