Opposition parties said the F-35 debacle shows the government is incompetent and cannot be trusted.

Government sources said the main contenders for fighter jets were the F-35s, Boeing Co’s F-18 Super Hornet and the EADS Eurofighter.

The Conservatives have a majority of seats in the House of Commons and are in no immediate threat politically, given that the next election is due in late 2015.

Reuters reported the main outlines of the government’s revised plan to acquire fighter jets last Friday.

The initial plan called for the F-35s to be delivered between 2017 and 2023. Officials, insisting the F-35 had not been ruled out, declined to say how long it would be before planes would be delivered under the new plan.

“We will take the time needed to complete this work, to get it right and ensure ministers have the best possible information,” a senior government official told reporters.

As part of the overall review, the defense ministry will look at whether the lifespan of the CF-18s can be extended beyond 2020.

Despite announcing in July 2010 it would buy the F-35, Ottawa never signed a binding contract with Lockheed Martin.