HALIFAX -- The Conservative government has formally accepted the first six of the long-delayed CH-148 Cyclone maritime helicopters.

Public Works Minister Diane Finley and Defence Minister Jason Kenney made the announcement Friday at the Shearwater air base in Nova Scotia in front of three of the Cyclones, which have been on the base for testing purposes.

Finley said she realizes the arrival of the first helicopters in the $5.7-billion project has taken far too long.

"In fact this procurement has had a torturous history, but in 2013 we brought in external experts and we committed to fixing this problem," she said.

"We announced last January we would put a plan in place to ensure the delivery of initial capability helicopters in June 2015 and through a lot of hard work and dedication we've kept that promise."

The original contract signed by the Paul Martin Liberal government in 2004 called for the Cyclones to be delivered in November 2008, with deliveries of all 28 helicopters completed by early 2011.

The Harper government signed a deal a year ago to amend its contract with Sikorsky Aircraft -- the U.S. manufacturer of the helicopter -- after repeated delays and problems meeting the original specifications.

As part of the renegotiation, the Royal Canadian Air Force revisited its list of expected capabilities, and was asked to spell out clearly what aspects were essential as opposed to what they would like to see in the aircraft.

Finley told reporters the helicopters that had been accepted were capable of being used on missions on warships, but she added work remained to be done on the aircraft.

"They're in accordance with amendments to contracts that were made, but we'll be continuing to work with Sikorsky on upgrades."

Evaluators of the Cyclones have previously raised questions about the helicopter's ability to stay airborne in the event of an oil loss. The so-called "run-dry" capability has been a concern since it was determined to be a factor in a fatal crash of the Cyclone's civilian version off Newfoundland in 2009.

When asked if the new Cyclones have the ability to fly without lubricant for 30 minutes, Kenney said yes.

Kenney said that 43 air crew and maintenance staff have been trained to operate the new helicopters, and that by 2021 the full contingent of 28 Cyclones will be operating on ships.

He said the new helicopters will be far more capable than the aging Sea Kings, which will begin to be retired.

The aircraft will be capable of flying up to 450 kilometres without refuelling, and will have a secure data link that allows it to exchange information with NATO allies.

"In short, the Cyclone is bigger, faster and more efficient and will increase the future effectiveness of Canadian military operations," he said.

A senior defence official told reporters after the announcement that the first group of helicopters will not initially be used for deployment, but for testing and other purposes such as transporting cargo.

He said the new helicopters will continue to be upgraded over the next few years and their capabilities will be expanded.

A second group of Cyclones with further upgrades is expected to arrive in 2018, he said, but those still won't meet the full military capability expected by 2021.

The Ottawa Citizen has reported that Department of National Defence documents express concern that the helicopter's engine does not have sufficient power for military use.

The defence official told reporters on Friday that the manufacturer is still working on upgrading the aircraft's power output.