TORONTO -- Ontario's auditor general says new ads from the Liberal government about its plan to cut hydro bills could be considered partisan.

The series of two taxpayer-funded ads, running on radio stations across the province, tells listeners that people will receive an average of 25 per cent off their hydro bills this summer and rate increases are being held to inflation for four years.

Auditor General Bonnie Lysyk says the ad likely wouldn't have passed under previous rules about government advertising.

The Liberals changed the criteria in 2015 and Lysyk said the new rules remove her discretionary power to approve or reject ads as partisan, reducing her office to a rubber stamp.

She says the hydro bill ads are a "pat-on-the-back" style of advertisement, conveying a positive impression of the current government.

Progressive Conservative Leader Patrick Brown has written a letter to Treasury Board President Liz Sandals, saying the government has "no authority to be spending hard-earned taxpayer dollars on partisan" ads to promote a plan that hasn't passed the legislature or even been tabled.