Mayor John Tory says the TTC may stop planning work on extending the Yonge subway north if the province doesn't commit to helping fund the future downtown relief line.

Tory, speaking Tuesday at the corner of Gerrard and Carlaw Streets, which sits along the relief line's proposed route, said he's puzzled by hesitation at Queen's Park to commit funding for the project, especially as Ontario has provided $150 million to help study it.

The line could open by 2031, but Tory says that timeline is entirely dependent on getting all three levels of government to pay for its construction.

That timeline is important, as studies have found that Line 1 will be running at full capacity at that point.

"This new line will be the next major step to relieve crowding on the Yonge line," Tory told reporters.

Mayor <a href="https://twitter.com/JohnTory">@JohnTory</a> crossing route of future Downtown Relief Line. How soon? Depends on provincial funding, he says. <a href="https://twitter.com/hashtag/topoli?src=hash">#topoli</a> <a href="https://twitter.com/hashtag/onpoli?src=hash">#onpoli</a> <a href="https://t.co/64JHs47Nug">pic.twitter.com/64JHs47Nug</a> —@johnrieti

Currently, the project remains in the planning stage, with city staff hoping to get a Class 3 cost estimate and schedule for the line by 2019.

More planning work has been done on the Yonge subway extension, which will connect Toronto and York Region, but Tory says the city and TTC may have to put that project on hold — especially because it's expected to increase riders on the already crowded Yonge line.

Transportation minister fires back at Queen's Park

Tory has been putting pressure on the province to fund future transit projects after its latest budget. (John Rieti/CBC)

At Queen's Park, provincial Transportation Minister Steven Del Duca pointed out the city's own reports say there's a considerable amount of work that still needs to be done on both projects, and that the government has been supporting that.

Del Duca said his government "is investing more in public transit in the City of Toronto than any other provincial government in history," and said he expects talks on future projects to continue.

Later, Del Duca issued a news release accusing Tory of "playing politics" by threatening to delay transit projects.

"The mayor isn't helping anyone, especially his constituents who want transit built in Toronto," the statement said.

Tory vows city will find a way to pay its share

Previously, the province has pointed out that Toronto hasn't committed its own money to building the relief line, however Tory says it will.

"We will sort out our contribution," he said, adding he had hoped his road-toll plan — blocked by the province earlier this year — would have paid for it.

The mayor had been pressuring the government to commit more money for transit and social housing in the lead-up to its recent budget, which he says lets the city down. He said the city can't afford to stop planning transit projects given Toronto's expected growth.

"We will build and we will build and we will build," he said.

"We are committed to building a system that will catch up."

Tory's executive committee is set to debate the next steps for the relief line and Yonge subway extension at its meeting next Tuesday.