Petro Canada has revised its estimates on the size of the oil spill off the southeast coast of Newfoundland. Officials say the spill involved up to 170,000 litres of oil, more than four times the original estimate.

Petro-Canada had said the Sunday morning spill at the Terra Nova offshore oil platform involved 40,000 litres of oil. On Monday afternoon, a company news conference revealed about 1,000 barrels had been tossed into the ocean.

The spill has created a slick about nine kilometres long and one kilometre wide.

The Canada-Newfoundland Offshore Petroleum Board has ordered a suspension of production operations at the platform. It is investigating the incident.

Federal Natural Resources Minister John Efford said a cleanup was a first step, with a "full investigation" into the cause of the incident to follow.

Crews are hoping to start a cleanup operation Tuesday, when seas are expected to be more calm.

Two vessels are on the site, ready to deploy booms and skimmers, and a third vessel is on the way.

However, Petro-Canada says it may only be able to recover about a quarter of the oil.

A mechanical failure has been cited as the cause of the spill, the largest in the province's six-year history of oil production.

The oil was pumped directly into the ocean Sunday morning at the Terra Nova platform, which has been producing oil since 2002.

* Coverage from CBC St. John's

John Downton, director of communications with operator Petro-Canada, said production on the platform was suspended when the incident was reported.

"Our operating principle is that we don't discharge," Downton said.

"We take it very seriously. We are looking into it to trying to find out what happened to make sure it doesn't happen again."

Downton said a failure occurred in the machinery used to separate fluids brought up to the platform. The fluids contain water and crude.

Bill Montevecchi, a Memorial University scientist who studies seabirds, said even a small amount of crude oil can be fatal to wildlife.

"This crude oil is the kind of stuff where the bird gets that black heavy, kind of sludgy stuff on it," Montevecchi said.

"It's just lethal. Period."