National has now watered down what was originally planned to reduce the impact on small business, farmers and volunteer groups.
Labour's spokesman for labour issues Iain Lees-Galloway said National had forgotten the lessons of Pike River. "National has significantly weakened it with changes based on anecdotal assertions and outright fearmongering by a small group of employers."
Workplace Relations Minister Michael Woodhouse said it was important to strike a balance between safe workplaces and unnecessary red tape, and he was "confident we have landed in the right space".
National's changes included exempting small businesses (fewer than 20 employees) in lower-risk industries from requirements to elect health and safety representatives or committees if workers requested it - representatives who have the power to order work to stop if there is a safety risk.
Those changes were welcomed by Business New Zealand who said the original bill was overly onerous for small businesses.
Although the exemption does not include small companies in higher-risk industries, the trade unions and Labour have objected to it saying it will exempt forestry and security companies.
FIRST Union General Secretary Robert Reid said the Government had caved to pressure from "irresponsible employers."
"Why should a forestry company with 12 workers be excluded when an insurance companies with over 500 workers is included, even though the greater health and safety risks lie with workers in the smaller company?" Labour's Phil Twyford referred to the death of 22-year-old Charanpreet Dhaliwal, who was killed on his first night as a security guard at a construction site in West Auckland.
He said the exemption for small business could exempt the security company "that sent Charanpreet to his death".
"The right to elect a health and safety rep is not some kind of nice-to-have. They have the legal right to investigate safety issues, raise issues with the boss, enter and inspect a workplace, and call in an inspector."
Mr Woodhouse said the changes were sensible.
"The amended Bill takes a risk-based approach to focus effort on what a business needs to do, what is "reasonably practicable" for it to do, and what is in its sphere of control."
National's changes also address concerns from farmers they would liable for any accident on their farm, even if it was a hunter or tramper.
The new bill will restrict the definition of 'workplace' to farm buildings and the areas immediately around them, as well as any part of the farm on which farm work was being carried out.
The farm house would also be exempted.
The impact on volunteer groups was also addressed by exempting totally volunteer organisations and volunteers involved in fundraising drives, sports teams, and extra-curricula school activities.