OTTAWA -- Canada's extended time in Afghanistan to train that country's fledgling army and police forces is expected to run taxpayers about half a billion dollars, not including the cost of repatriating equipment.

The estimate was laid before the House of Commons defence committee, as it considered a request by National Defence for a budget top-up.

Defence Minister Peter MacKay says the total operational estimate for the 950 soldier contingent, over four years, is expected to be $522 million by the time the mission comes to an end next year.

The figure, like all defence estimates, is the incremental cost, the amount of money the department spends over and above the routine expense of maintaining an army.

The training mission, based in Kabul, was established in mid-2011 as combat operations in Kandahar province ceased.

It is slated to end in March 2014 with the last Canadian soldiers and equipment out of the country by the following August.