Chris Luxon insists National's controversial grocery policy is in line with the party's principles.
National has joined New Zealand First, in campaigning for a break-up of the two Foodstuffs co-ops - something almost 500 owner-operators have criticised in an open letter this morning.
Labour wants to separate the supermarket chains from their wholesale arms, while the Greens want to establish a state-owned grocery chain.
Luxon told Mike Hosking National is the party of enterprise, but it's also the party of competition.
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