Legislation giving workers Monday off when Waitangi Day or Anzac Day falls on the weekend has passed its final hurdle in Parliament.
It is the first Opposition members' bill to pass since the National-led Government came to power in 2008.
The Holidays (Full Recognition of Waitangi Day and Anzac Day) Amendment Bill, or so-called Mondayisation bill, in the name of Labour MP David Clark, passed its third reading by 61 votes to 60 on Wednesday evening.
Labour Party deputy leader Grant Roberston earlier told the House that New Zealanders have missed out on holidays in the past few years.
"The origins of the bill, Mr Speaker, were in 2010 when both Anzac Day and Waitangi Day fell on weekends and there was no holiday on Monday for either of them.
"That year, New Zealanders only got nine of the 11 public holidays that they are entitled to under the Holidays Act. That's not fair - and this bill seeks to give hard-working New Zealanders a fair go."
Mr Robertson said the law change would not diminish the importance of Anzac Day (25 April) and Waitangi Day (6 February).
The National and ACT parties opposed the bill.
National MP David Bennett said his party doesn't support the bill, partly because it is not that significant, while colleague Mike Sabin said Anzac Day means much more than getting a day off work.