Canada's new armoured jeeps are popular with troops for the protection they afford and their air-conditioned interiors. But it appears they have developed a disconcerting problem - cracks in their floors.

Lt.-Col. Jacques Beaudoin, the jeep project manager, says 85 per cent of the Mercedes G-Wagons sent to Canadian troops in Afghanistan have developed cracks in the floorboards.

CTV's Matt McClure, reporting from Kabul, says he had a look at the cracks Monday afternoon.

"They're not very visible to the eye in most cases. But there are holes in the floorboards beneath the passenger and driver side that are about the size of your finger," he told Newsnet.

"These have developed apparently because of the stress the vehicles are facing on the rough terrain here, and also perhaps because of the heavy armour these vehicles have been equipped with to protect the troops."

Beaudoin says the cracks are of a cosmetic nature and are not compromising the safety of the occupants.

"They have no impact on the structural integrity of the vehicle and no impact on occupant safety or mine protection. This is not a major concern at this point.''

He says tests conducted on prototypes last year uncovered floor cracking at the 80,000-km mark.

The problem seems to have only arisen in vehicles with the 700-member Canadian NATO contingent in Kabul.

About one-third of the 1,000 vehicles Canada has ordered have been delivered, and about 100 of them are now in Kabul.

Officials from the Defence Department and Mercedes-Benz have visited Kabul and assessed the problem. Because the vehicles are still under warranty, Mercedes says every single one will be retrofitted with an improved floor at no cost to taxpayers.

They will be fitted with a double floor extending to the vehicle's firewall. Beaudoin says the correction will be tested and implemented on the production line.

The military sped up delivery of the vehicles last year, after two Canadians were killed by a land mine while driving an unarmoured Iltis jeep near Kabul.

Canada has also bought 1,060 GM Silverado utility vehicles.