I have recently just purchased the Asus RT-AC66U router to replace the standard telecom router for my UFB connection.
Setup: Fibre to the door -> optical network terminal -> ethernet -> asus router -> ethernet -> computer
Here is a screenshot of the Asus WAN page to help guide my explanations:

I have called telecom multiple times for their internet connection settings which resulted in the following parameters:
First off I tried using the instructions on the telecom site for broadband settings for non-telecom routers (UFB tab) DID NOT WORK
I then tried the same settings but changed the username and password with the following combinations:
Username | Password
user@xtrabb.co.nz | password (DID NOT WORK)
user@xtrabb.co.nz | <myusername> (DID NOT WORK)
user@xtrabb.co.nz | abc123 (DID NOT WORK)
<myusername>.xadsl@xtra.co.nz | abc123 (DID NOT WORK)
I have tried the latest asus firmware for this router and also tried the merlin build ( NEITHER OF THEM WORKED )
If you have any experience with Asus routers, I have also tried their Quick Internet Setup using the PPPoE connection type and the above username and password combinations. It does not allow you to leave the username and password blank as Telecom UFB settings suggest... The connection times out saying: cannot detect internet connection type.
The Telecom settings suggest that the VID must be set 10 for your UFB connection. No where in WAN page settings can I set the VID.
I don't really want to resort to flashing the router's firmware as there is a risk that it can damage the router if not done properly. This is a risk I do not want to take with an expensive router such as this.
Calling out to anyone that has setup an Asus router with Telecom UFB or to anyone that has any suggestions.
Any help is much appreciated.
Cheers Damian.