Labour says sweeping health and safety changes have failed to protect New Zealanders, citing figures that show workplace deaths have not reduced.
However, Workplace Relations Minister Michael Woodhouse said the number of deaths and serious injuries at work was clearly trending downward, and Labour were "cherry picking" statistics.
"It is premature and it is nonsense. Because the trend is inexorably downwards," Woodhouse said. "To take a slice of a part of a year ... is just quite wrong."
So far this year 43 people have died in workplace accidents. That is the same number for all of last year.
New workplace health and safety rules came into effect on April 4, as a response to the Pike River mine tragedy in 2010, in which 29 men died.
It was watered down after objections in the National caucus, and businesses with fewer than 20 workers do not now need health and safety representatives.
But businesses deemed high risk need to have safety representatives, regardless of size.
Controversially, dairy, sheep and beef farming were not classified as "high risk" industries, despite having had a high number of fatalities in the past five years.
That meant farms don't need to have health and safety representatives.
Woodhouse faced ridicule last year when it emerged worm farming and lavender farming were on a draft list of high-risk industries. When categories were later confirmed they weren't high risk.
Labour's associate workplace safety spokeswoman Sue Moroney said the 43 deaths this year showed an "urgent rethink" was needed on workplace safety.
"We always said that the agriculture sector should never have been exempted from the regulations.
"Agriculture continues to be the sector with the largest number of deaths since the law change in April - with 44 per cent of the total deaths recorded between May and the end of September."
Woodhouse told the Herald that injury and death rates were clearly trending downwards. Fatalities over the past five years were 49, 48, 57, 48 and last year 43.
"It is margin or error stuff with four weeks to go in the year ... if she wants to have a game of 'my statistic is bigger than your statistic', I'll win. Because the trend is undoubtedly downwards.
"In respect of the legislation, it has only really been in place for six months. This was a generational change both in the law and our attitudes towards health and safety ... I have done hundreds of meetings ... and I know the attitude is changing."