A bill to restrict union access to the workplace will enable employers to undertake better business planning, according to Minister of Labour Kate Wilkinson.
Parliament debated the Employment Relations Amendment Bill on Thursday afternoon.
The bill extends the 90-trial work trial, which at present applies to business employing fewer than 20 people to all employers.
It also introduces a requirement for union representatives to gain consent from employers before visiting workplaces.
Ms Wilkinson admits abuse is not a widespread problem, but says where it does occur it can cause significant disruption.
She says providing discretion allows businesses to plan around work stoppages and employee availability.
The Green Party says giving employers two days to respond to union requests will not help employees facing urgent bullying or sexual harassment problems.
The bill passed its first reading by 64 votes to 57 with the support of the ACT and United Future parties.
Unions to hold protests
Forty-two unions representing more than three-quarters of New Zealand's union members are participating in a campaign against the Government's changes.
The Engineering, Printing and Manufacturing Union says the legislation is unnecessary and meaningless.
EPMU national secretary Andrew Little says the changes are driven by ideological and political motivations - not by concern from employers - and they will only change things for the worse by reducing workers' rights.
Unions will hold rallies in Auckland, Wellington and Christchurch on Saturday and in Dunedin on Sunday in a bid to change the Government's mind.