Before registering a business name, in order to risk been sued, it is absolutely crucial that you ensure your new name does not infringe upon another parties legal rights, and in particular another parties registered trademark or similiar business name. At the very least have a professional search conducted for you.
The more similar your name or brand is to another....."the more fingers your cross", because you can be sued!
eg: Google, Groogle & Scroogle - The Age
Registration of a Business name, Company name and even a Domain name will not protect your name, such registrations will not give you exclusive rights to use, market or even advertise the name in commerce, unless you have ensured as much as possible that your name or logo will not infringe upon any existing trademarks that are currently registered, or pending registration in Australia.
If your name or logo is found to be infringing, you can be sued by the trademark owner.
As Business name registration does not protect you, or provide you with exclusive rights to marketing and advertising of the name, it is very important that you investigate protecting your name or logo with a Trademark registration in Australia.