A: Many businesses just need an ABN to get started. Some businesses need a licence, others don't. Best to check with your state business regulator, if you're not sure. To find out if you need to go down that track, best to have a chat with someone already running a business like this nearby.
Like in NSW, the regulatory authority is Office of Fair Trading: here are some notes on licences:
In Victoria, the licensing authority is Consumer Affairs
South Australia, Consumer & Business Services
Western Australia, Small Business Development Corporation
Queensland, Tasmania ABLIS
Northern Territory, Dept of Business, Business Licensing