The introduction of new coins on Monday is likely to cost some businesses dearly.
The 5c coin will disappear and the 10c, 20c and 50c coins will be replaced with smaller, lighter, coins minted in Canada.
It is a move the Reserve Bank ways will save the country $2 million a year.
But a vending machine service company says the cost of changing the thousands of vending machines around the country would be felt severely by some operators.
Adam Jennings, a technical engineer with Vending Direct, said each machine would cost about $160 to change to accept the new coins and that cost had to be met by the owner.
Coca-Cola, which has about 10,000 machines around the country, said the change would be "very expensive" but would not elaborate.
However, at $160 a machine it could face a bill of $1.6 million.
Vending machines must be changed to accept the new coins as well as the old for the three-month transition period - then changed again to accept only the new coins.
After November 1 the old coins will not be legal tender but the Reserve Bank will continue to accept them.
The bank said the older versions of the 10c, 20c and 50c coins were very large and the 50c coin was one of the largest circulating coins in the world.
The newer coins would be easier and cheaper to use and handle.
The large size was a legacy of pre-decimal days. New Zealand changed from the British system using pounds, shilling and pence to decimal currency on July 10, 1967.
The 5c was being withdrawn because inflation had reduced its value so much.
The Reserve Bank said a 5c coin was now worth less than half a cent was worth in 1967 when decimal currency was introduced.
The Auckland City Council says it has already changed the 820 multi-bay parking meters covering 6000 spaces to accept both new and old coins.
On-street parking manager Chris Geerlings said the cost of replacing the meters' electronic chips was about $20,000.
He said about 500 of the machines were new and would accept credit cards, coins and text payments. However, more than 90 per cent of parking payments were still in coins.
- NZPA