TORONTO - The New Democrats are ramping up the pressure on the Liberals to reveal the costs of a cancelled gas plant in Mississauga, Ont., by seeking to involve the auditor general.

Leader Andrea Horwath has written to the watchdog to ask that he investigate what impact the decision to stop construction on that site will have on taxpayers.

She says it's particularly important given the Liberals pulled a similar move in Oakville, and refuse to say how much cancelling those contracts will cost even though some reports say it could be as much as $1 billion.

Both Horwath and Tory Leader Tim Hudak say the plan to relocate the controversial plant west of Toronto, 11 days before the Oct. 6 Ontario election, is a clear play for votes.

The Liberals say they were simply listening to the community when they decided to move the plant.

They also note that both Hudak and Horwath have promised to cancel contracts themselves if elected.

The Tories have vowed to kill a deal with Samsugn while the NDP want to scrap a GO Train refurbishment contract with a Quebec company and send those jobs to North Bay.