 The new coins have a unique electromagnetic signature which enables modern vending machines to determine coin counterfeiting and foreign coins , and it was estimated the changeover would remove nearly $5 million of foreign coinage from circulation.The change to smaller coins is also advantageous to Australia, as the outgoing 5, 10, and 20c coins were of the same size and weight as Australian coins of these denominations, and were easily confused by shopkeepers and retailers, as well as being usable in Australian vending machines and parking meters.As of 1 April 2018, there are five denominations of coins in regular circulation