TORONTO - The New Democrats say they're worried electricity rates for peak hours could increase if the Ontario government lowers off-peak rates.

Premier Dalton McGuinty says there needs to be a larger price differential between the two rates to encourage more people to change habits to take advantage of time-of-use pricing.

However, McGuinty wouldn't say if lowering the off-peak rate would mean an increase in the peak rate, and now suggests it's a communications problem.

He says the government may not have done a good enough job of explaining the pricing options available to people who do laundry or dishes late at night.

NDP Leader Andrea Horwath says she's disappointed McGuinty ducked the question about increasing the peak rate for electricity, which is already nearly double what Ontario residents used to pay 24 hours a day.

Progressive Conservative Leader Tim Hudak says the smart meters installed to tell exactly when people are using electricity are not helping anyone lower their hydro bills.

Hudak says smart meters are nothing but a "McGuinty tax machine."