Saskatchewan's premier says he is "cautiously optimistic" and hopeful Ottawa's plan to purchase the Trans Mountain pipeline for $4.5 billion works.

Scott Moe has been outspoken about wanting to see the proposed expansion of the pipeline built, saying not completing the project carries an economic impact to Saskatchewan

"I hope this works," Moe told reporters on Tuesday.

"This isn't likely the way that I would have went about it, you know, I think, nationalizing this piece of infrastructure."

According to the government, the lack of access to tidewater cost provincial oil producers an estimated $2.6 billion and cost the province an estimated $210 million in taxes, royalties and other revenue in 2017.

'Last choice'

Moe called the move from Ottawa "a last choice." He said there are other means the federal government could use, such as restricting infrastructure payments to B.C., which Moe believes Ottawa should do.

He expressed concern about what potential message the purchase sends to investors, saying Ottawa paid Kinder Morgan to effectively leave.

"What has changed? We have a different proponent on the pipeline ... as far as the regulatory environment with respect to ensuring this pipeline is built, what has changed?" said Moe.

He pointed to B.C. premier John Horgan's comments on the project as well as what he says is a lack of a construction plan.

"We still don't see shovels in the ground. We've seen an announcement here this morning, we need shovels in the ground, we need construction to start on this piece of infrastructure," Moe said.

"I hope this starts to narrow the differential. I hope this is beneficial to the Saskatchewan price we get for our energy commodities."

Moe said that unlike Alberta, his government will not shelve legislation to restrict energy exports to B.C. and intends to pass it, with only days left in session.

Despite his vocal support for the project, Moe said Saskatchewan will not pick up the tab for any construction costs because the project carries Alberta oil. He said now every Canadian is paying for it.

Saskatchewan NDP leader Ryan Meili also expressed optimism, and said the federal government took leadership on the matter.

He did not, however, support the call to restrict federal infrastructure dollars to B.C.