Yesterday, Mr Key said he'd now received advice from the Department of Labour on the issue after the advice pointed out that the next time either day fell on a weekend was in 2015 and it was not until 2021 that both Anzac and Waitangi Day fell on a weekend in the same year.
The department had told Mr Key the cost to the economy for an individual day if Monday-ised was $200 million or $400 million in a year when both were Monday-ised.
"The recommendation from the Department of Labour is not to Monday-ise them" Mr Key said. But Labour leader David Shearer said Monday-ising the holidays was "a terrific idea" that most New Zealanders would support.
"We're entitled to 11 public holidays a year, for these two public holidays falling on a weekend that means we miss out.
"Why can't we have those holidays?" Mr Shearer said.
Once the estimated $200 million cost for Monday-ising each holiday was averaged out across the number of years between when it would occur and across the population affected, the cost would be "a few cents per person".
"I think it's just a bit mean really." The issue was to be discussed amongst National MPs at today's caucus meeting, before the Government decided whether it not it would support Mr Clark's bill.
Mr Key said he intended seeking further information on the matter including advice that New Zealand was " at the reasonably generous end in terms of the number of holidays we have compared to other countries around the world" apart from Australia.
Even if National decides to vote against Mr Clark's bill, it may pass anyway with its coalition partners the Maori Party and United Future still deciding whether to support it.
United Future leader Peter Dunne said it was more likely than not he would support the bill which will come up for parliamentary scrutiny in six weeks time.