TORONTO - Ontario's governing Liberals are on the attack, warning voters the Progressive Conservatives can't afford to keep some of their campaign promises.

Liberal campaign co-chair Greg Sorbara came out swinging at a plan by Opposition Leader Tim Hudak to eliminate the debt retirement charge from hydro bills if the Tories win the Oct. 6 election.

Residential customers are charged about $6 a month to pay down the stranded debt left over from the old Ontario Hydro, but the two parties disagree on how much is outstanding.

The Liberals say it is $14.8 billion, while the Tories talk about a residual stranded debt of $7.8 billion.

Sorbara says the Tory plan would mean $3.7 billion that is supposed to pay down the hydro debt in the next four years would not be paid.

He calls the plan irresponsible and says the debt will continue to grow if it isn't paid off, and wonders if the Tories' plan to shift the debt burden from homeowners to businesses.

The Tories and the New Democrats both promise to remove the eight per cent provincial portion of the HST from electricity and home heating bills if they win the election.

The Liberal government is on the defensive over rising electricity bills and the impact of the HST, especially on gasoline and home heating.