The New Democrats are calling for the province's budget watchdog to look at how the Liberal government's hydro relief plan will affect consumers' bills.
Leaked cabinet documents suggest ratepayers could be hit with large increases after an initial drop.
The document that was leaked to the Progressive Conservatives contains a projection that electricity bills will drop this year, rise slightly for four years while increases are held to the rate of inflation, and then rise quickly after that.
The government dismisses the document as containing outdated projections.