I login from https://one.nz/#sign-in 
That works for me.

djtOtago:

 

I login from https://one.nz/#sign-in 
That works for me.

 

Yup, that's how I'm logging in. I go there, click on the "Internet and Landline" tab, fill in username and password (from my password manager), and then I'm shown the page in the my screenshot above.

Hmm, I've just tried it again and this time instead of clicking on the "Internet and Landline" tab I just left it on the "My One NZ" tab and entered my details. I was able to log in and see both my home internet connection and my mobile phone plans. I thought that they were previously under two different logins but I guess not any more. Anyway, I was able to get in and do what I wanted. Someone from One might still like to check out that reCAPTCHA error though.