A shortage of the new slimmed-down 20c coins has concerned retailers bracing for the Christmas shopping rush.
But the Reserve Bank is promising that newly ordered bulk supplies of the coins will ensure demand is met over the festive period.
"It is only the abnormal demand for 20c coins which has meant the Reserve Bank has had to manage issues of this denomination," said Reserve Bank currency manager Brian Lang.
"The pattern of demand for new coins has been markedly different to that for the old coins."
In the past week, the Reserve Bank had distributed an extra 4.75 million 20c pieces - close to the number issued in a typical year. And a further 10 million of the coins will arrive in New Zealand over the next few days.
The Newmarket Business Association said yesterday that the new supplies would "allay some of the fears" for retailers who had been unable to get their hands on 20c coins.
Association head Cameron Brewer said he had spoken to the major banks and claimed all had "internal communications" about the shortage.
"This ... doesn't inspire much confidence in our central bank. Retailers have got enough on their minds in December without worrying about running out of change."
Mr Lang said the bank had issued almost as many 20c coins (49.6 million) as 10c coins (53 million) by November 30. In the past, the number of 20c pieces would have been about half that of the 10c coins.
The bank was unsure why the pattern of coin issues had changed.
"It might reflect changes in retailers' change-giving practices, or New Zealanders might be continuing their old habits of dropping coins into jars and drawers just as they did for the old large coins."
Mr Brewer said he did not accept the excuse that the bank had been caught out by unexpected demand.
"Given the many years of work leading up to this new coin transition, such a staggering miscalculation ... should never have happened."