The cost of having an extra day off every seven years was estimated to be 0.11 per cent of the average wage bill. Unions argued the costs would be so minimal that most businesses would not notice them.
The government labour service estimated each extra day off would cost NZ $200 million but has since said this was an overestimate.
Some submitters argued the legislation was unfair on employees who worked an irregular roster, because they would not get the Mondays off.
The Retailers Association said: "There are vast numbers of people who work weekends, or perhaps Tuesday to Thursday. None of these people have enjoyed 11 public holidays, ever, as most holidays have been "Mondayised" in the past, stripping them of that entitlement."
But Dr Clark assured the select committee considering his bill that it was drafted in such a way that no one would be penalised.
If the national holidays fell on a weekend, and the day would otherwise be a working day for an employee, the public holiday had to be treated as falling on that day. Anyone working on a weekend Anzac or Waitangi Day had to be paid time and a half and accrue a day in lieu.
The main economic argument in favour of the bill was that it was believed the extra holiday would boost the local tourism sector.
Tourist operators said hotels sold 1.5 more rooms each during long weekends.
A holiday park at Hot Water Beach said it booked 457 people on a long weekend in 2012 compared with 72 bookings in 2011 when Waitangi Day fell on a weekend.
Some submitters argued that it was narrow-minded to discuss the pros and cons of additional holidays in purely economic terms.
The Dunedin Community Law Centre noted that New Zealanders worked more annual hours than workers in Britain, Canada, Japan and Canada and giving workers more time with families could provide significant gains in physical and mental health.
Mondayisation
Pros
* Boost to domestic tourism from additional holidays.
* Potential for increased productivity from rested workers.
* Mental and physical benefits of workers having more days off/time with families.
* Opportunity for additional events to commemorate national days.
* Creates consistency with Christmas, Boxing Day, New Year's Day.
* Impact on employers is minimal.
Cons
* Would make no significant difference because many people work weekends.
* Potential cut to productivity from reduced working days.
* Takes attention away from special nature of the nationally important days.
* Penalty rate makes it uneconomic for some businesses to open on public holidays.
* New complications for companies in pay entitlements.
