Here is the T&C:
- Bonus & Eligibility: 55,000 bonus offer is only available to new American Express Card Members who apply online for the Qantas American Express Ultimate Card, are approved and spend $3,000 on eligible purchases on their new Card in the first 3 months from the Card approval date. This is a limited time offer which may be withdrawn or changed at any time without notice. Card Members who currently hold or who have previously held any Card product issued by American Express Australia Limited, in the preceding 18 month period are ineligible for the Bonus Qantas Points offer. Previous and existing bank-issued American Express companion cardholders are eligible for this offer (cards issued by: Australia New Zealand Banking Group Limited, Commonwealth Bank of Australia, National Australia Bank, Westpac Banking Corporation).
Even though Westpac dumped Amex to have it managed using the Amex portal. It's still issued by Westpac, with the Westpac Branding and can't be acquired directly with Amex. I feel the T&C above still applies. However this may be different from reality, who knows.