A legislative committee passed a motion asking the auditor to launch a formal investigation into the costs of privatizing the government agency.
The auditor is also being asked to examine the amount of money the governing Liberals claimed would be saved by privatizing Ontario Northland.
The New Democrats and Conservatives say they don't believe it will save money at all.
Tory Vic Fedeli says he believes that the severance payments alone could cost the province about $450 million.
New Democrat France Gelinas says the ONTC is important to northern residents, and she expects new Premier Kathleen Wynne to make good on her promise to listen to them.