50 Cents - Elizabeth II 4th portrait, magnetic

New Zealand's switch to nickel-plated steel for the 50-cent piece was part of a 2006 coinage reform that also reduced the physical size of the dollar and two-dollar coins and eliminated the five-cent piece entirely — the most significant overhaul of the country's circulating coinage since decimalization in 1967. The new smaller, lighter coins were designed partly to align with vending machine and parking meter infrastructure across the Tasman, where Australian coins of similar dimensions were already in use.

The magnetic property is a direct consequence of the steel core, useful for automated coin sorting but occasionally problematic in older mechanical coin mechanisms calibrated for the cupro-nickel predecessor.