Hundreds of jobs and millions of dollars in new development in downtown Sudbury are in jeopardy because of stalled building plans.

Across the tracks in the city's core is a centrepiece of the new downtown master plan.

It's a vacant lot trumpeted as the future home of something called the Inno-tech Park.

Downtown Development Corporation director Susan Thompson said two companies were lined up to build offices at the location, bringing with them hundreds of professional jobs.

But she said those firms are now looking to build elsewhere.

"It's at risk of maybe not getting off to the rocket start we thought it would have," said Thompson.

One reason the master plan is in limbo is because CP Rail has rejected the city's request for new road and pedestrian crossings at Larch and Cedar Streets, deeming it unsafe and at risk of snarling train traffic.

Thompson said the focus should instead be on relocating the downtown train yards, something her group is working on.

"The main resistance is at the city level, but it's actually moving ahead, unfortunately, without them right now," said Thompson.

Sudbury city councillor Frances Caldarelli said she sees the railway lands as the key to revitalizing the city's downtown.

"We've got do something because it blocks off a whole section of the city that really could be so useful to the downtown," said Caldarelli.

The city said it's still in talks with CP Rail about making its ambitious downtown master plan a reality.