The argument for me is the same as women in porn and prostitution.
The fact that there are a small minority who are aok with it and all goes well is dwarfed by the massive harm to so many vulnerable women.
There are terrible things reported about surrogacy around the world.
If we lived in autopia where all the women doing porn, prostitution, surrogacy. Were doing it through genuine choice, enjoyed it, there was no financial or other incentive. Then I'd say ok then.
We are nowhere near that place and so the answer from me is a blanket no.
Incidentally we have similar rules in the UK to NZ by the sound of it.
Suddenly there's a big push to change to the USA style.
The fact it's not fair that people 'have' to go abroad to get what they want is pushed as a reason to change the laws. For convenience. And because not enough women want to do it for altruistic reasons. And because the women who carries and births the baby is recognised as it's mother. So old fashioned! So difficult! Must be changed.