The City of Toronto wants to expropriate airspace above the proposed Rail Deck Park if negotiations to purchase the space continue to stall.

Rail Deck Park is a proposed 20-acre park that would be built above the rail corridor between Bathurst Street and Blue Jays Way. The project is expected to cost around $1.7 billion.

However, Toronto does not own airspace above the proposed site, a major hurdle that has stalled the early planning stages of the project.

A report to be considered by Mayor John Tory's executive committee on Jan. 23 lays out a plan to expropriate the airspace to move forward with the ambitious park.

"We are taking the next important steps to make progress on Rail Deck Park," said Tory in a news release. "Moving forward on acquiring this air space brings us closer to getting Rail Deck Park underway."

The report says negotiations to acquire the airspace at "fair market value" with its various owners have had "no success to date."

With bargaining at an apparent standstill, deputy city manager Josie Scioli is recommending that Toronto initiate expropriation proceedings for a three-acre portion of airspace between Spadina Avenue and Blue Jays Way.

Toronto budget chair Gary Crawford said the city is in need of more parks downtown, but added that a cost to expropriate the land must be established before moving forward.

"There could be extensive costs, it could be reasonable, we just haven't seen that yet," he told CBC Toronto.

When combined with a private proposal by Oxford Properties Group to build a three-acre park on the other side of Blue Jays Way, the total new greenspace could be up to seven acres.

Acquiring that airspace would allow the city to proceed with the first four acres of the park, roughly equivalent in size to Grange Park, the report notes.

Toronto says the ultimate goal is to complete the full 20-acre park, though the report says it may be built in phases "to help manage the anticipated cost and complexity of the project."