Many backpackers choose to work whilst they are in Australia
in order to supplement their funds. However, first you must ensure you have the correct visa. If, for example, you are travelling on a short-term visitor visa, you are not permitted to work. If you do, this constitutes a clear breach of your visa conditions which is likely to result in the cancellation of your visa and you may be deported. You may further face a 3 year ban from returning to Australia on most provisional visas.
Many backpackers on a visa that allows them to work find casual employment in the vineyards in summer and spring, bars (both bar work and waiting work), temporary agency work and so on. Jobs are advertised in the daily newspapers and backpacker and temporary work agencies can also help place you.