National Defence has reserved the right to build fewer of the Conservative government's vaunted Arctic offshore patrol ships in order to stay within the project's $3.1-billion budget envelope, according to federal documents.

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.

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.

One official "stressed that current process of establishing cost caps for projects is problematic and that Department and Government pricing and budgeting strategy need to better reflect the uncertainties that are readily apparent in procurements involving significant design/development work," said minutes from a fall 2008 meeting attended by both the head of the navy and the senior official in charge of procurement.

"More specifically, 'caps' placed early in projects ... are often inappropriate on shipbuilding projects."

The minutes were obtained under the Access to Information Act. Officials warned there is a need to have "flexibility built into the [request for proposals] that in the event that cost projections are too low, the [project management office] can still return to government with a recommendation to accept fewer hulls or reduced capability."

The Tories initially started out in 2006 insisting that three heavily armed icebreakers be constructed, but the estimated cost of $1 billion per ship and the fact they could be used only in the Arctic forced a retreat.

They eventually settled on a proposal for six to eight patrol ships capable of operating in first-year ice. That was quietly changed last year to six ships, according to documents and interviews with officials.