Unions have also objected to the weakening of collective bargaining and ability to dock workers' pay for industrial action such as working to rule. It also allows employers to choose not to be part of a collective agreement even where the workforce have voted for one.
Workplace Relations Minister Michael Woodhouse said National had campaigned on the changes to make the labour market more flexible and was now delivering on them.
"Flexible and balanced employment relations legislation is essential for business to grow while ensuring protections for workers are retained. This Bill strikes the right balance to promote business growth while also retaining protections for workers."
Council of Trade Unions Secretary Helen Kelly said it meant New Zealand now had some of the worst worker protections in the OECD.
"This law attacks workers when they are most vulnerable; when they are negotiating for a new job, when their employment is at risk. Many workers will even lose their rights to tea and meal breaks."
Robert Reid, General Secretary for the FIRST Union, said the changes were unnecessary and driven by ideology rather than the economy. He said the Government had spoken about its wish for wages to increase, but was now blunting the tools that allowed that to happen.
"Collective bargaining is one of the most effective tools workers have. It works. If the government had any interest in lifting wages it would strengthen collective bargaining not attack it."