The Labour Party has sought to embarrass the Prime Minister over his statements about changes to labour laws.
The Government has announced plans that include extending the 90-day trial for new workers to all companies, instead of just those with 20 or fewer employees, and restricting union access to workplaces.
Prime Minister John Key said on Monday that, under the 90-day scheme, employers have to give a reason for sacking a worker.
But Labour leader Phil Goff questioned that in Parliament, saying the law explicitly removes such a requirement.
Mr Key said that good-faith employment provisions retained under the legislation require employers to tell workers why they've been sacked.
Labour Minister Kate Wilkinson was unable, however, to tell Parliament whether the good-faith provisions override the law.