Doubt is being cast on the integrity of United Future's confidence and supply deal with the Government.
It follows a party member raising concerns about how partial asset sales are addressed in the arrangement.
The member says the deal is based on shareholdings, not the voting rights approach National's applying to ownership restrictions.
Labour's Finance spokesman David Parker believes Peter Dunne's confidence and supply deal with the Government has been compromised.
"He says that he's protecting New Zealand by ensuring that less than half of these companies are sold and yet we now see details allowing non-voting shares to effectively mean over half of the companies can be sold."
The United Future leader's vote is key to the Government getting its legislation through.
John Maynard of People's Power Ohariu, says there are strong feelings about the issue in the electorate.
"A large number of voters in our electorate have come to us and said 'we thought that our member of parliament was opposed to the sale, what's he signed this agreement for?' We're looking at a whole range of activity, in fact some 600 people made submissions to the Ohariu people's select committee."
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