Domain renewal scams are becoming increasingly more common, especially in Australia where the .com.au data can lead to real addresses. This is a scam from Domain Register Pty Ltd (ACN: 127 506 807), who send what appears to be an invoice for a domain renewal. This invoice is generally for a domain which is similar to your existing one, eg if you own domain.com.au, they've sent you an invoice for domain.net.au.
They hide the following in the fineprint:
The text is "This is an invitation to register, disregard this letter if you are not the proprietor or if you do not wish to register.", which is in very small grey text on a grey background. The cost of registering the domain is far higher than nearly every registrar in Australia, meaning you will end up paying significantly more for a domain that you don't need.
Conetix suggests that you read all domain related invoices and emails carefully. If the provider is known to be a scammer (as is the case for Domain Register Pty Ltd), discard it immediately.
Please feel free to forward your correspondence through to Conetix if you believe it's a scam and one of our support staff will help evaluate it for you.