Metrolinx President Bruce McCuaig told local media the agency may even attempt to advance current schedules, since the Toronto Transit Commission says any subway construction is at least five years in the future.
"I think we're going to take some time to look at the entire program and see if it still is optimal to start Sheppard in 2016 and start Finch in 2015," McCuaig said.
McCuaig's affirmation follows Mayor Rob Ford's comments to also convert the two LRT projects to subway construction. On Tuesday the City Council approved advancing the Scarborough Line as a subway project, also approving a 1.6% property tax increase to fund Toronto's share of the estimated cost of at least C$2.5 billion.
Ontario Transportation Minister Glen Murray also says the change in rail mode for the Scarborough Line, which he supported, won't affect current plans for LRT on the two projects.
"We're locked in now to those routes. We can't constantly be changing them," Murray said, adding, "Scarborough was a 30- or 40-year-old grievance that needed to be resolved and there was a very clear position from a mayor and council by majority vote. It is a democracy and there is always a tension between sticking to the plan and being respectful of overwhelming mandates."
Already under construction is the Eglinton-Scarborough Crosstown LRT, part of Ontario province's C$8.4 billion capital program expanding rail transit in Canada's largest city.