A pipeline leak has spilled 380,000 litres of light petroleum within five kilometres of a provincially designated grizzly bear zone in northwestern Alberta, with some of it reaching a nearby creek.

Producer ConocoPhillips Canada says in a statement posted Tuesday on its website that the leak of condensate, a liquid produced with natural gas, was seen at a pipeline right-of-way near its Resthaven gas plant about 65 kilometres northeast of Grande Cache last Thursday afternoon.

Company staff also observed condensate in nearby Webb Creek.

"The pipeline has been shut down and isolated and we have activated our emergency response plan," ConocoPhillips said.

"We have deployed over 150 responders to the site with equipment to contain the release and mitigate any environmental impact."

The company said it reported the leak to the Alberta Energy Regulator. It said it has erected fencing and amphibian barriers to keep wildlife away from the area. A wildlife biologist is also on site.

The regulator said in a news release Tuesday that it had issued an environmental protection order to ConocoPhillips directing the company to contain the release and prevent it from spreading, while controlling access, collecting water and soil samples and submitting a final report to the AER.

The provincial agency said its staff are at the site, which is in the Little Smoky caribou range and near a core grizzly bear zone. It says condensate was visible as a sheen on the surface of the creek for about 4.5 kilometres below the pipeline leak.

The creek flows to a beaver dam and then into the Simonette River. The AER said the sheen was not visible on the river but an analysis indicated hydrocarbons present at slightly above minimum detection limits.

The regulator said no cause for the leak has been established and an investigation is underway.

One of the key uses of condensate is to dilute raw Alberta oilsands crude to allow it to flow in a pipeline to market.