The new coins from New Zealand will be released on the 31st of July.
There will be a 3 month transitional period in which both old & new coins will be in circulation.After that,the old coins will be no longer legal tender,but you will still get full face value for them from the Reserve Bank of New Zealand here in Wellington.The 5c. coin will no longer be issued.The 10c. coin will be a copper-coloured one.
The 20c. & 50c. coins will be smaller in size & of a different metallic composition.Here's a link;
https://www.newcoins.govt.nz .
Aidan.