Each day without production means more than C$2 million ($1.7 million) in delayed revenues for the company.

The 160,000 barrel-a-day Terra Nova project was idled on Sunday when up to 1,000 barrels of crude leaked into the ocean, 350 km (217 miles) southeast of the Newfoundland coast, creating a large slick.

Petro-Canada is in the midst of an investigation into why an oil-water separation system malfunctioned, causing the spill, Martin told reporters.

"I can't put a time frame on our own investigation necessarily, because I don't want to limit it," he said. "In orders of magnitude time-wise, we're talking a matter of a few days -- possibly as early as tomorrow -- but it could be a few days."

Findings will then be presented to the Canada-Newfoundland Offshore Petroleum Board, which will determine if it is safe to restart the field without more oil spilling from the floating production, storage and offloading vessel, Martin said.

He said he did not know how long the regulator would take to review the results of company's investigation.

Petro-Canada is using absorbent booms to sop up the crude, which has formed patches of slick covering about 57 square km (22 square miles), Martin said.

Some authorities have called it the worst oil spill in the region. But it is tiny in comparison with the notorious Exxon Valdez spill in 1989, when 260,000 barrels of crude flowed into Alaska's Prince William Sound.

Petro-Canada's partners in Terra Nova are Exxon Mobil Corp. , Husky Energy Inc., Norsk Hydro, Murphy Oil Corp., Mosbacher Operating Co. and ChevronTexaco Corp.

The operator reported an unrelated spill Thursday from a drilling rig, 2 km (1.2 miles) northeast of the Terra Nova production vessel. The mobile drilling rig Henry Goodrich leaked about 2.5 barrels of oil, which is now mostly cleaned up, Martin said.