The Labour Party says it would make Government departments and agencies favour local firms ahead of those overseas.
Party leader Phil Goff says its procurement policy ensure jobs stay in New Zealand.
He says companies like KiwiRail should be made to manufacture rolling stock in this country rather than buying it abroad.
Mr Goff says Government contracts are at present won on cost alone, and Labour's policy would require departments to also consider the wider impact on the economy.
He says the policy is compliant with World Trade Organisation rules and would bring New Zealand into line with many other developed nations.