Saskatchewan's Attorney General Don Morgan said the province has hired Regina law firm MLT Aikins to assist with its carbon tax appeal at the Supreme Court of Canada.

Morgan estimates the costs in the range of $400,000 and $500,000.

"It is a significant amount of money, make no mistake, but we think the importance of having a strong precedent and having the best representation we can have for our province is absolutely critical."

He said MLT Aikins, which has offices across Western Canada, approached the premier offering its assistance with the Supreme Court case.

The tentative dates for the hearing are March 17 and 18, 2020.

Morgan said the government was looking for diversity in argument, and is looking for the government's lawyers and its hired help to provide "some of the best arguments presented in Canadian courts."

He said the province's argument at the Supreme Court will differ from its previously unsuccessful challenges in Saskatchewan and Ontario. Both courts upheld the constitutionality of a federally imposed carbon tax.

In May, Saskatchewan's Court of Appeal ruled in a 3-2 decision that the federal plan was constitutional. In June, Ontario's Court of Appeal ruled 4-1 in favour of the federal government's position.

Earlier this week, Morgan announced the province gained intervenor status in Alberta's carbon tax challenge, which will be argued next month.

"We're looking at every place where carbon tax is being argued we want to be able to assert our position and look to other courts to try and benefit us as we go forward," Morgan said.

The government is using in-house lawyers from its constitutional law branch to argue court challenges on the carbon tax in Alberta and previously in Ontario and Saskatchewan. Morgan said the fees to the province are for court filings, travel and hotel. He estimated those costs being "a few thousand dollars."

The constitutional law branch is one of five branches in the Legal Services division. The total budget for the division is $10.8 million.