OTTAWA -- Brad Wall is taking aim at the prime minister, who he believes decided to skip the premiers’ meeting when it became clear it would be more than just a "photo op."

"Let's be very clear," Wall, the premier of Saskatchewan, said in an interview with CTV News. "My understanding is the prime minister wanted to attend this meeting basically for a photo op on the [Canada Pension Plan]."

Wall says the premiers invited Prime Minister Justin Trudeau to "have a more substantial discussion" on an issue like health care, "but not a photo op. And so then he decided not to attend."

The premiers are meeting in Whitehorse this week, to discuss a range of issues including internal trade and the promised legalization of marijuana.

A spokesman for Trudeau said he was unable to attend the premiers' meeting because of a scheduling conflict. Trudeau was in Ottawa to announce the name of the athlete who will be Canada’s flagbearer at the upcoming Olympics in Rio de Janeiro.

"However, the prime Minister is very proud that our government is building strong bilateral and multilateral relationships with all provinces and territories," Cameron Ahmad wrote in an email to CTV News. "That’s why he decided to serve additionally as minister of intergovernmental affairs."

The federal and provincial finance ministers agreed last month to increase CPP contributions to eventually increase the program's payouts. The increase to contributions will cost employees and employers starting in 2019. The finance ministers had given themselves until the end of 2016, and it was thought to be a win for federal Finance Minister Bill Morneau that they achieved it early.

Wall was thought to oppose the increase, but Saskatchewan signed on along with every province except Manitoba, which has a new Progressive Conservative government, and Quebec, which has its own pension plan. The ratification was delayed, however, when British Columbia said last week it needs more time to explain the deal to its citizens.

Wall is one of the few conservative-leaning premiers left at the table. He's a minority voice when it comes to climate change, arguing Saskatchewan's economy can't afford any kind of carbon pricing when oil and gas revenues have already plunged.

The spokesman for Trudeau said reducing emissions will make the Canadian economy more competitive, and that the first ministers' agreement on climate change "underscores our collective commitment to achieve greater reduction in our emissions, and work together on carbon-pricing mechanisms best suited to provincial and territorial economies across Canada."

At the last meeting between Trudeau and the premiers, they agreed to set up a number of working groups, including on carbon pricing. Trudeau suggested in an interview Wednesday that Canada will have carbon pricing across the country, with or without provincial agreement. Canada's most populous provinces have already introduced or are preparing to introduce carbon pricing, whether through a carbon tax or cap and trade program.

Wall says he has great concerns about Trudeau and federal Environment Minister Catherine McKenna suggesting they'll move without all of the provinces on board.

"Now the prime minister and the federal environment minister seem to have predetermined the outcome of that [carbon pricing] working group. That's not collaborative federalism, and that's not what I think we agreed to," Wall said.

The Saskatchewan premier compared carbon pricing to the idea of an automakers' tax during the 2009 recession, which would have hit Ontario's economy the hardest.

"We have a concern about a new national carbon tax at a time when our economy can least afford it. The energy sector is still reeling, obviously, from low prices," Wall said. "A carbon tax would disproportionately impact ... the energy sector, a very important sector in this country."