Labour MP Nanaia Mahuta is critical of the Government's proposed Health and Safety Reform Bill, saying it has watered down some of the changes - putting Māori workers at risk.
The contentious workplace health and safety legislation was debated in Parliament this afternoon.
It was due to have its committee stage debate yesterday, which is when parties can push for changes to the legislation, but that was held up by last-minute talks with smaller parties wanting substantial changes.
The bill has caused controversy.
Under recent amendments, small businesses will not have to elect health and safety representatives - rather, only those on a list of 57 industries that are considered high-risk will require one regardless of their company's size.
Ms Mahuta said the Māori Party should not support the National Party's proposal to make it optional for lower-risk industries with less than 20 employees to have elected health and safety representatives.
She said it had a real opportunity to stand up for safety in the workplace for all workers.
"I would like to see the Māori Party walk their talk and, if they are so concerned about the health and safety of all workers on all worksites, then they should oppose this legislation in favour of strengthened law reform that will cover all workers.
"I'm really clear that the Māori Party can change the outcome of this particular issue and they should look to implement and support the recommendations of the Royal Commission."
Workplace Relations and Safety Minister Michael Woodhouse said the majority of farming businesses would not require a health and safety representative under the proposed new legislation.
He said most farming businesses would not meet the high-risk threshold the government has set for injury and fatality.
But Ms Mahuta was critical of that exclusion and said Māori were particularly at risk.
"The two highest recorded industry sectors for workplace deaths are agriculture and forestry, and the data does show that those are the areas where there is a high proportion of Māori being employed, especially in forestry...
"All workers deserve the best protection through health and safety law and that's the point for the Māori Party. They're talking a big game, but can they deliver on an issue as important as this? I challenge them to walk the talk.
Māori Party's Marama Fox: 'We take the lives of workers seriously'
Māori Party co-leader Marama Fox rebuffed Ms Mahuta's criticisms.
Ms Fox said the party had lobbied hard to have a list of high-risk industries released, and that small businesses that were considered high-risk were not exempt.
"Now that was our major area of concern. If they're a high-risk industry... then no matter what the size of your business, you request a health and safety officer, you must have one."
She said the Labour Party was just playing politics.
"It's almost a little bit schizophrenic. On the one hand they've said we're delaying things and we need to hurry up, and on the other hand they're saying 'you've not done enough what are you going to do about it?' So actually we have been negotiating in good faith with the [Workplace Relations and Safety] Minister since before the second reading.
She said the party has put pressure on the National Party and has not allowed the contents of the bill to be watered down.
"We know that as a support party to the Government there are opportunities for us to influence the Government or vote against them, that's our independence.
"We have done all we can in trying to fight on behalf of workers, and not just now, but in the past.
"We initiated the forestry review and that will be for small groups of forestry workers or large forestry cooperations.
"We take the lives of workers seriously and we have been lobbying and working and negotiating with this Government as strong as we possibly can, to ensure that we can make the changes that they are willing to come halfway to us on.
"Now granted we won't win everything, but today, in the House, the changes that will be made to this legislation will be because of the minor parties and not because of any of the lobbying that's been done by any of the opposition parties, so I think it would be fair to ask - what has the opposition achieved?
"We are absolutely sure that this new legislation, with the things we've been able to strengthen in it, is a better piece of legislation than what currently is there. If this legislation is voted down, we will not be in any better position than we currently are."