Speakers at a trade union rally in Auckland have told workers proposed changes to employment law will hand all the power to employers.
About 4000 people were at the often-raucous rally in Manukau on Wednesday, to protest against the Employment Relations Amendment Bill.
If passed, the bill will let employers walk away from collective bargaining in the event of a stalemate.
Other changes include removing the requirement for employees to be on a collective contract for the first 30 days of a new job.
Council of Trade Unions president Helen Kelly told the rally the Government's own advice says the changes will drive down wages.
Engineering Printing & Manufacturing Union national secretary Bill Newson says the bill is a further attack on workers' rights.
"In the last four years our government has introduced more than 20 law changes that affect the work place, including the ones we are talking about today. Every single one of those changes goes against working people and goes in favour of tipping that balance of power up for employers."