TORONTO - The Ontario government spent nearly $700,000 on advertising aimed at promoting its controversial plan to harmonize sales taxes last spring, newly released documents show.

It planned to spend about $2.5 million to buy space for the ads, which were to include newspaper and radio spots in French, English, aboriginal and ethnic media, according to documents released Thursday by the Department of Finance.

But only the online ads about the HST -- which cost $600,000 -- were used because the print ads were rejected by the auditor general Jim McCarter for violating Ontario laws.

"Namely, we found that a primary objective of these ads is promoting the partisan political interests of the governing party," McCarter wrote in an April 20 letter to the Department of Finance.

The ads aimed to persuade the audience about the government's opinion of the merits of the "benefits" of the HST, rather than providing facts and explanation, he wrote.

"It would be difficult for the audience to distinguish fact from opinion and they do not present information objectively in tone and content," he added.

Under Ontario law, the auditor general must approve all government advertising in print, radio and television -- but not over the Internet.

The Liberals put the legislation in place several years ago to curb what they described as abuse of taxpayers' money on partisan ads by the previous Conservative government.

Now the Liberals are trying to bypass their own rules by using a loophole to circumvent the auditor, opposition parties charged.

"It's clear (McGuinty's) ads broke the intent of the provincial law he brought in," said Progressive Conservative Lisa McLeod, who called on the Liberals to pay back the $700,000.

"The auditor general rejected the ads, they shouldn't play, he's now playing them and it's just plain wrong."

NDP Leader Andrea Horwath called the online advertisements a "colossal waste of money," adding they were inappropriate, at least in spirit.

She also questioned the choice to use Narrative Advocacy Media, an agency whose managing director Amanda Alvaro used to work for Liberal Gerard Kennedy, an MP who used to sit at McGuinty's cabinet table.

"It's quite disconcerting and yet again shows a pattern of this government giving plum contracts to their friends," Horwath said.

Narrative Advocacy Media, which was hired through a competitive process, was paid $95,000 for its work on the campaign, the documents showed.

It was hired a year ago by the government to provide "strategic communications" about the 2009 budget that unveiled a plan to merge the provincial sales tax with the federal GST.

Finance officials provided the documents to reporters on Thursday, the same day they were expected to be released through freedom of information requests made by opposition parties.

The documents arrived the same day the government launched a new $1.6-million ad campaign about the HST and tax reforms, which were vetted by the auditor general.

The print ads, which highlight an income tax cut that took effect Jan. 1, invite readers to "take a closer look at Ontario's new tax package" by visiting a government website.

The government argues the current ad campaign is needed to make sure people have a reliable source to get facts on the HST, which takes effect next July.

"The fact that ads were eventually approved by the auditor general and are in today's newspapers shows the process works," a finance official said.

"We have abided by the law and are informing Ontarians about these important tax changes that will create jobs and growth."