The Lansdowne Park redevelopment plan has already been delayed by two years, and the city's biggest union is helping finance a group that wants to cancel the project.
The Canadian Union of Public Employees (CUPE) donated $15,000 to the Friends of Lansdowne, a group that took the city to court, alleging it sole-sourced the redevelopment contract.
It's reported that CUPE is against the project because it believes its members won't get much work in the redevelopment process.
"It's completely inappropriate or wrong," said Roger Greenberg, one of the business leaders with Ottawa Sports and Entertainment Group.
"We have already agreed with the union that the staff position at Lansdowne, which are currently a union position, will continue to be a union position."
Coun. Scott Moffatt told CTV Ottawa he's frustrated the union got involved.
"They are free to do what they will, but at the same time you'd hope that they'd respect the majority of this city and council," said Moffatt.
"I think it's more disappointing that it's a group that the city deals with on a day-to-day basis."
A provincial judge ruled last month that the city didn't break any rules when it awarded a contract to redevelop Lansdowne Park to OSEG. Friends of Lansdowne is now appealing that decision.
With files from CTV Ottawa's Stefan Keyes