A couple of years ago, Labour proposed a Local Government (Protection of Auckland Assets) Amendment Bill, designed to stop the new Auckland supercity from privatising its strategic assets against the will of its people. Now, they're proposing an equivalent at a national level. The State-Owned Enterprises and Crown Entities (Protecting New Zealand's Strategic Assets) Amendment Bill would effectively entrench public ownership of SOEs and other strategic assets such as TVNZ, Radio New Zealand, and the Crown Research Institutes, requiring a 75% supermajority or a referendum before they can be sold.
It's a solid, democratic idea, which rightly recognises that this decision belongs to the people and that politicians (inevitably tainted by corrupt donations from would-be purchasers) cannot be trusted to make it unsupervised. Sadly, it is unlikely to ever become law. Standing Order 262 [PDF] requires that any proposal for entrenchment be passed in the Committee stage by its proposed supermajority. National - ideologically and corruptly in favour of privatisation - is unlikely to vote for it. So, even if the bill is drawn, or put up by a future Labour government, its sole effect will be to put National on the spot and remind everyone that they cannot be trusted when it comes to deciding ownership of state assets. Which is a perfectly valid purpose for a member's bill, but sadly one that is unlikely to lead to positive change.
(If Labour really wanted to put National on the spot, they'd get the bill endorsed by a public referendum first. But I doubt even that would convince National to vote for it. The entire problem is that they genuinely don't care what we think about this issue, and are quite willing to sell public assets with no mandate and in the face of enormous opposition from the public).