A U.S. company has put crowdsourcing to work in the search for a missing Malaysia Airlines jetliner, inviting internet users to comb through satellite images of over 3,100 square kilometres of ocean for any sign of wreckage, the company says.

Colorado-based DigitalGlobe Inc. used two of its satellites to collect imagery from an area between the Gulf of Thailand and the South China Sea where the Boeing 777-200ER with 239 passengers and crew on board was at first believed to have crashed after it went missing early on Saturday, the firm said on its website Tuesday.

The effort by DigitalGlobe was launched just before Malaysia's military indicated the flight might have gone way off course, which could place its last known location hundreds of kilometres from where DigitalGlobe collected satellite imagery for its crowdsourcing project.

The company placed the images on its crowdsourcing website Tomnod on Monday and invited the public to join in the search for any sign of the plane, whose disappearance has become one of the most baffling mysteries in recent aviation history.

The flight last made contact with civilian air traffic control roughly midway between Kota Bharu, a town on Malaysia's eastern coast, and the southern tip of Vietnam while flying at an altitude of 10,670 metres.

"If there is something to see on the surface [of the water], we will see it," Luke Barrington, DigitalGlobe's senior manager for geospatial big data, told the Denver Post. "But the question is if we are looking in the right area," he added.

Plane off course

A Malaysian military officer told Reuters that Flight MH370 from Malaysia's capital of Kuala Lumpur to Beijing appears to have turned around and made it to the Strait of Malacca, to the west of peninsular Malaysia, instead of to the northeast of the country where initial search efforts were conducted.

Navy ships, military aircraft, helicopters, coast guard and civilian vessels from 10 countries have crisscrossed both coasts of Malaysia in an effort to find the plane, deepening the mystery over its disappearance.

The DigitalGlobe imagery collected for the crowdsourcing project covers over 3,100 square kilometres where the Gulf of Thailand meets the South China Sea, the company said on its blog.

DigitalGlobe said in a statement that it was working to best handle "an unprecedented level of web traffic" and interest in supporting the search.

DigitalGlobe is asking web users to tag any clues that may help locate the missing plane. If users start tagging some regions in large numbers, DigitalGlobe plans to use a computer algorithm to detect that, Barrington earlier told ABC News.

DigitalGlobe used a crowdsourcing campaign when Typhoon Haiyan struck the Philippines in November, as the company relied on thousands of volunteers who tagged over 60,000 objects of interest to help tally the destruction, according to the firm.