It is not compulsory to use the ® and ™ symbols in Australia, but it is beneficial for a business owner to do so when using their trademark in social media posts. Use of the ™ symbol gives third parties notice that the business owner considers a particular sign to be a trademark. Use of the ® symbol must only be used next to a registered trademark, and it is an offence to use it in Australia in relation to anything other than a registered Australian trademark.
The (r) and tm symbols are not mandatory in Australia.
As a trademark owner, the (r) and tm symbols should be used in social media posts like Facebook, LinkedIn and Twitter if possible. This can prevent infringement as well as keep your trademark from becoming generic.
The ™ symbol can be used for both registered and unregistered trademarks, providing notice to others that the sign is considered a trademark.
The (r) symbol is only permitted next to a registered trademark. In Australia, using this sign for anything except an officially recognised Australian trademark can be legally punished.
If unsure if a mark is registered in Australia, one should indicate that using the tm symbol.