An environmental review of Enbridge Inc.'s (ENB) controversial Northern Gateway oil pipeline must finish by the end of next year, the Canadian government said Friday.

A joint review panel considering the environmental effects of the pipeline's route from Alberta to a British Columbia port must finish its work by Dec. 31, 2013, and the federal government will decide whether to approve the project within six months, by the summer of 2014, according to a statement by the Canadian Environmental Assessment Agency.

The deadline for the project comes after the Canadian government passed a law this summer that limits the timeframe for environmental reviews of major economic projects such as mines and pipelines to two years or less. The new law is necessary to prevent projects from being delayed by lengthy reviews, the government said.

It wasn't immediately clear whether the deadline changes the project's schedule, since regulators have said they hoped to finish their work by the end of 2013 anyway. An Enbridge spokesman wasn't immediately available to comment.

Northern Gateway envisions sending 525,000 barrels of oil a day to the port of Kitimat in British Columbia, for shipment on tankers to China and other buyers in Asia. The pipeline is expected to cost about 6 billion Canadian dollars (US$6.01 billion) to build, and is scheduled to start operating in 2017.

Environmental groups and some native groups oppose the pipeline's construction due to the risk of spills on the land and coastline. Enbridge has said it plans to take extra precautions on safety for the project. Canada's ruling Conservative Party government has also thrown its weight behind such projects, saying building pipelines to the west coast is strategically important for the country's energy industry, which currently relies on exports to the U.S.

Write to Edward Welsch at edward.welsch@dowjones.com and to Paul Vieira at paul.vieira@dowjones.com