As collectors of modern Australia will no doubt know, on 4 January 2016 Australia Post increased its basic postage rate from 70c to $1. The increase in the postal rate led to shortage of 30c. stamps which were needed to make up the difference from the previous 70c rate. To solve the problem, Adelaide GPO used an old printing machine to counter-print an emergency issue of six 30c stamps. Featuring three kangaroos and three koalas, the six stamps were produced in small numbers and were used until more of the standard 30c. Crocodile stamps were printed in Melbourne. Now, these six are creating much interest amongst collectors, with some sets selling for than AUS$100.