This number keeps calling me and after reading the comments about it being Telstra calling about a new connection I realise it's a scam because I haven't applied for a new connection from Telstra.

Telstra provisioning of new Internet service. I called back and step through to confirm upcoming appointment.

debt collection

I called back number (02) 8070 2247 reached IVR of Telstra. IVR was asking for the number I was called on so that they can retrieve my details.

It is a telstra support number. If you are getting a new installation from them, they will contact you if required.

Just called me on my mobile.. Answering machine "setting up a Telstra phone connection"
Asked me to Press 1
I am not stupid enough to press 1 for it.

This number has been calling me for a week now on and off.
The number left text messages on my mobile citing "setting up a Telstra phone connection for Jeff".

Also related caller (most likely related), "No Caller ID", has been ringing and leaving the same message.

Received 2 calls from this number, no message. If it is from telstra then perhaps they should set up a message to make it easier for people to confirm.

This is an automated Telstra service to confirm details for an upcoming connection.