The Westpac do allow
Joint and supplimentary card holders (I have both) .
This allows the additional Priority card and doubles the highest airpoints earn rate

I applied for a Westpac World Airpoints Mastercard and it just approved. Process was a little slow but not too painful. The guy who sorted it out said to just go into a branch and ask for a partner's card to be sent out - I think that's a supplementary card on me rather than a joint account card? Assume that means the APD and SP earn from both cards will automatically accrue to my AirNZ account.
I also noticed on the Westpac website (not on the AirNZ card comparison website) that the Westpac World card also has a "Two complimentary Valet Parking eVouchers each year" benefit that I didn't get with the Kiwbank card. Probably means two with my card and not another two with a supplementary card, but four with a joint card?

I received 4 parking vouchers just for myself. Although that might be an error as they sent me two credit cards (in my name) for reasons that had the Westpac team scratching their heads....

Yes two per account not two per card

I was told the same thing, but there is a short application form to fill out. Your partner will also be AML checked, unless they are a Westpac customer. Take ID and proof of address, and ideally both go together.

when they get their card they have to go into the branch again, with ID, to get the card pinned.

When I originally applied for the new Westpac card and account, my card arrived within days.
But we have now been waiting over a month for my wife's 'additional cardholder' card. Multiple emails and phone calls to Westpac to chase it up, but still no luck on an ETA or even confirmation if it is being sent.

Two vouchers turned up on my account... will be see what happens when I request a second card for wife.

A difference between the discontinued Kiwibank card and the "replacement" Westpac Airpoints World Mastercard. The Westpac card does NOT earn SP with tax payments (see point 1) whereas with the Kiwibank card did. A minor frustration as paying tax via credit card (inc cash surcharge) was a good way to topup SP if required.

Using the AMEX via RewardPay can be good for this.

For me I�ve chosen to not get the westpac card and just stick with the ANZ card and AMEX due to this and other exceptions on the Westpac card.

Thanks - I hadn't looked into AMEX as it wasn't accepted widely last time I had one. Taking a quick look at the website I couldn't see any reference to Status Points - only Airpoints Dollars. Is it possible to earn SP using the Amex card?

$250 spend = 1SP

Most supermarkets, petrol stations, big box retailerd and online stores seem to take it these days.

Can anyone confirm that paying IRD payments using RewardPay using AMEX earns Status Points?

No mention of earning Status Points on AirNZ or RewardPay websites. So would assume no.

AirNZ - Reward Pay