Apple is taking an unusually high percentage of every sale made with Apple Pay. All of the AU banks were opposed to the amount they were asking for and were basically "holding the line" against them. They've even asked to be allowed to oppose Apple as a single entity to force their hand, which is unusual.

ANZ broke ranks (and I think someone from Apple actually moved into their ranks).

I'm not sure if they got an exclusivity deal for doing so, but the rest of the banks are still not happy with what Apple are asking for.

They are aware that it had been something of a coup for ANZ, with lots of people opening new accounts with them just for this reason.

The banks aren't doing this to be difficult, any extra costs that Apple charge will eventually be passed on to the customer. The banks do not feel they should have to absorb it. But if that's what we all want, that's what we'll all get eventually.