United Future leader Peter Dunne says making the following Monday a holiday when Waitangi Day and Anzac Day fall on weekends is sensible and long overdue.
Mr Dunne is likely to hold the deciding vote on whether a Labour Member's bill, as well as another member's bill to increase paid parental leave, get past their first readings in Parliament on Wednesday.
And he says it should not come any surprise that he would support moving public holidays to Mondays.
Mr Dunne last year campaigned to extend paid parental leave, saying parents should be able to have the option to spend more time with their newborns.
The bill would extend the period from 14 to 26 weeks.
Labour says it also has support from Mana, New Zealand First, the Greens and the Maori Party which would give each bill a majority of 61 to 60 to get past the first readings.
Finance Minister Bill English has re-stated his intention to use his financial veto to scuttle the paid parental leave bill if it reaches its third reading.