One day after the Toronto Transit Commission fired two senior executives who were in charge of the troubled Toronto-York Spadina subway extension, the agency announced up to $185 million more is needed to complete the project.

In a report made public Friday, the TTC detailed four options, each with different timelines and costs ranging from $150 million to $185 million.

TTC staff is recommending the cheapest route that will see the extension completed by the end of 2017. According to the report, the cost-sharing agreement for the project means the majority of the additional price tag would have to be borne by Toronto.

"The amount Toronto would have to find would be $90 million," TTC CEO Andy Byford said Friday. "The remaining $60 million would be attributable to our funding partner, York Region."

The report recommends that council find the extra funds in the TTC's 2014 operating budget surplus, as well as by deferring other projects and selling property.

The original budget for the 8.6-kilometre extension was $2.6 billion. It was originally supposed to be completed this year, but the completion date was later pushed to fall 2016.

Byford said there were a number of factors, including issues with contractors and two harsh winters, that delayed the project. It is currently 70 per cent complete.

"We understand the frustration," Byford said. "I'm as keen as anyone to get this project across the line. We tried our damndest to have it done by 2016 and for a myriad of reasons, circumstances conspired against us."

Friday's report will be debated ruing a TTC board meeting on March 26.