From little things, bit things grow - rapidly. Melbourne-based web developer Tim Mansell acquired his first bitcoins - a form of digital currency - as an investment early last year when the price started skyrocketing. Now the novelty has worn off, but he's found he can use the currency to pay for his everyday expenses, including something as simple as buying a sandwich.

Melbourne shop, Hero Subs, was one of the first food franchises in the world to accept bitcoin. Now, the city has the country's most bitcoin-enabled businesses, according to a global digital currency map that updates numbers every hour. There are at least 52 Melbourne shops and 28 Sydney businesses accepting the virtual currency, and the lesser known "litecoin."

Sam Tate pays for his breakfast at Melbourne's The Little Mule Cafe using bitcoins. Credit:Michael Clayton-Jones

Bitcoin bypasses banks and financial institutions by allowing individuals to pay each other and online merchants with coins held in a digital wallet. Transferred using mobile and web apps, its popularity has grown from being an efficient way to pay for goods online to being used in mainstream bricks-and-mortar shops.

Mr Mansell, 31, said: ''I spend just to support the economy because if no one spends their coins and everyone hoards them then it's not going to survive or flourish.''