OTTAWA (Reuters) - Canada, faced with a politically controversial decision over how best to upgrade its fleet of fighter jets, will extend the life of the existing planes to 2025, an official said on Tuesday.

Canadian Forces CF-18 fighter jets take part in military exercises near Keflavik, Iceland April 5, 2013. REUTERS/Cpl Pierre Habib/Canadian Armed Forces/handout via Reuters

Canada’s aging 80 or so CF-18s had been marked for retirement around 2020, but Ottawa’s difficulty in making up its mind means they must now fly for longer. Some of the jets are more than 30 years old.

“We will be extending the life of our CF-18 fleet to 2025 to ensure that Canada has a multi-role, fighter-jet capability throughout the next decade,” said a spokeswoman for Defense Minister Rob Nicholson.

She did not say how much the upgrade would cost.

In 2010, Canada’s Conservative government announced a sole-source contract for 65 Lockheed Martin Corp F-35s but changed its mind in 2012 after a parliamentary watchdog roundly criticized the decision.

Ottawa then launched a more thorough study of the four most likely replacements and is in the process of deciding whether to hold an open competition or confirm the original decision to buy the F-35s.

The replacement file is particularly sensitive for the Conservatives, and critics suspect the government will put off its decision until after the next federal election, set for October 2015.

A source with direct knowledge of the matter told Reuters in early September that Canada would likely choose between the F-35 and Boeing Co’s F-18 E/F Super Hornet.

That would mean the elimination of Dassault Aviation SA’s Rafale and the Eurofighter Typhoon, jointly made by BAE Systems PLC, Finmeccanica SpA and Airbus Group NV.

The $400 billion F-35 program, the largest in Pentagon history, is already late and well over budget.