Our small change just got smaller

The new 50c, 20c and 10c coins. Picture / Mark Mitchell

New 50c, 20c and 10c coins will be introduced on July 31 in the biggest change to New Zealand currency since decimalisation in 1967.

And the historic changes will include the end of the road for the 5c coin, which will be phased out until it is no longer legal tender from November 1.

The Reserve Bank announced the change yesterday. It will mean 230 million new coins will be minted - a far bigger exercise than the introduction of the $1 and $2 coins in 1991.

The new coins will retain the same design but will be smaller and lighter. The new 10c coin is to be copper coloured. The one- and two-dollar coins will remain the same.

Reserve Bank currency manager Brian Lang said there would be a transition period of three months until October 31 during which time both old and new coins could be used.

"From November 1, you will not be able to use the old coins, including the 5c coin, but you will always be able to redeem them at the Reserve Bank."

The central bank said it had been working closely with other banks, security companies, vending machine suppliers, retailers and community groups over the past year to ensure a smooth transition.

New coins had been provided to the vending industry, giving it time to adjust before November. In some cases it was a simple computer re-calibration. In others a new mechanism would be needed.

The Reserve Bank has also worked closely with blind people's groups to ensure the coins could be used easily.

Graeme Riddell, from National Vending, which in 1991 became the country's first vending machine manufacturer, said a programme had been put in place and the industry had received plenty of warning.

Samples had been tested and, though there could be teething problems, "it won't turn us on our ear".

"Most are prepared and organised for it," Mr Riddell said.

The new coinage is intended to give a coherent and logical set of coins that are more convenient for the public, easier for those handling bulk cash, and less costly to manufacture.

It is understood that will save the taxpayer about $2 million a year.

Most old coins are expected to be out of circulation four to five weeks after the new ones are distributed.