Current Australian 5-, 10- and 20-cent coins are the same size as the old Australian, New Zealand and British sixpenny, shilling and two shilling (florin) coins. In 1990. the UK replaced these coins with smaller versions, as did New Zealand in 2006 - at the same time discontinuing the five-cent coin. The Australian 50-cent coin is a large coin. It weighs 15.55 grams and is 31.51 mm across.