In the early C19th, when William Wilberforce was camapigning to abolish slavery in Britain's colonial posessions, he met with strong opposition from the British establishment. Few of his opponents were bold enough to say that they actually approved of slavery. Instead, abolition would be "impractical". It would be bad for business and bad for the empire. The abuses which the abolitionists had highlighted were exaggerated and not widespread (there's a great example of this in the Earl of Belmore's speech on the Slavery Abolition Act 1833 here).
The Maori Party's contribution on the Fisheries (Foreign Charter Vessels and Other Matters) Amendment Bill, which abolishes slave-fishing in the New Zealand fishing industry, fits perfectly with this long tradition:
We know that the changes may mean that some iwi will no longer be able to operate. Big companies are better able to absorb the costs of changes, but those iwi and other operators who fish low-yield catch, cannot. There is a real risk that it will threaten their business, no matter how small they are. We believe that the Māori fisheries settlement must be durable. The Crown must act in good faith to ensure that we as Māori have a fair opportunity to catch up with our industry counterparts.
Iwi leaders told us, as they did also to the Ministers and anyone else who bothered to listen, that the alleged breaches of human rights issues—the widespread abuse that was being discussed—was never proven in an inquiry. It was their absolute belief that the legislation that evolved was an approach that was sort of like a sledgehammer to a peanut. They always knew that there could have been a far more effective approach to resolving issues than what was eventually developed.
In the end, they supported the bill. But its clear that they didn't want to, and wanted to keep slavery on charter vessels for a few more years for the profit of their big iwi backers. And that is simply an appalling position to take.
(Still, it could have been worse. When the UK abolished slavery, it compensated slave-owners for the deprivation of their "property" - compensation Britain's elite former slave-holders are still benefiting from today. At least we didn't see our Parliament approving a similar deal of compensating people we should be prosecuting for obeying the law they should have obeyed all along).