The Canadian government has revealed a plan requiring oil and gas companies to reduce emissions by 35% to 38% from 2019 levels over the next six years, in a step aimed at achieving the government's strict climate goals.

The government proposes a cap-and-trade system starting in 2026 to help the industry reduce pollution without reducing production.

Canadian Environment Minister Steven Guilbeault said in a press statement that the plan is "ambitious but practical."

He added in a statement: "It takes into account the global demand for oil and gas, the importance of this sector to the Canadian economy, and sets a strict but achievable limit."

However, the long-awaited proposal sparked immediate opposition from two of Canada's major oil-producing provinces, Alberta and Saskatchewan.

Alberta Premier Danielle Smith said the announcement deliberately attacks Alberta's economy, and that her government will develop a "constitutional shield" in response to the proposal in the coming months.