The Manitoba Liberals are accusing Brian Pallister's government of going against its word by using tax dollars to promote a PST cut.

During the 2016 Manitoba election campaign, the Progressive Conservatives promised to eliminate all public spending on partisan advertising.

The party also said it would empower the auditor general to review all advertising and dismiss any promotional materials found to be in violation of the rules.

Liberal Leader Dougald Lamont said the government is breaking its promise by advertising an upcoming reduction of the provincial sales tax to seven per cent.

"There's no public service element to this," Lamont said. "It's not telling people to go get vaccinated. It's not telling people about a new program they can take advantage of. It's really just spending public money to promote the party in power."

Spend ad money on fighting meth: Lamont

The province says the ad campaign — featured on billboards, print, radio and social media — will cost $173,000. The billboards will be up for about four weeks, but the campaign will be shorter in other media, the province said.

Lamont argued those advertising dollars would be better spent on discouraging people from using methamphetamine. He asked for that when the government launched an education campaign last year about cannabis.

"We haven't seen anything like that at all, but they are breaking their own promise and spending how much money on billboards, on radio ads that frankly … in my opinion, they should be paid for by the PC Party," he said.

"They shouldn't be paid for by government."

The auditor general so far does not have the authority to halt government advertisements.

In a statement, the province said it is spending considerably less than the former NDP government did on promoting budget initiatives. The NDP committed $302,000 to hyping its budget initiatives in 2015, the government said.

"We think it's important to inform Manitobans the provincial government is keeping its promises and taking action to make life more affordable by reducing the PST to seven per cent on July 1," the province's email statement said, in response to a question about why it was engaging in what could be seen as partisan advertising.

"Reducing the PST to seven per cent is an action of government that may impact the purchasing decisions of Manitobans."

In 2015, Pallister called for an independent review of all government advertising. He argued the NDP's "Steady Growth, Good Jobs" campaign was solely promotion for the governing party, since it contained no details about the construction it was touting.

That campaign cost nearly $1 million, The Canadian Press reported.

Lamont believes the Pallister government's advertising is tied to the possibility of an early election, which he previously speculated could happen as early as this spring.