OTTAWA - Federal documents say National Defence has reserved the right to build fewer of the Conservative government's vaunted Arctic offshore patrol ships -- or further water down the capabilities of the warships -- in order to stay within the project's budget envelope.

Military planners have struggled, almost from the moment the government was elected in 2006, to fulfil Prime Minister Stephen Harper's pledge to put armed "ice capable" ships in the far North to enforce Canada's sovereignty.

The government plans to build six light icebreakers for $3.1 billion.

Minutes from a series of internal planning meetings running from 2007 to 2009, obtained by The Canadian Press, paint a picture of frustration among officials who are charged with designing and building ships that critics have said are more suited for the coast guard.

At issue is the government's demand for a Canadian-built warship, but insistence on strict budget discipline, something one official called "inappropriate on shipbuilding projects."

Other officials warned there needed to be flexibility built into the system so that project officials could accept fewer ships -- or the same number of ships, but with less capability.