Another non-tariff barrier

I do not see the problem here. I do see a lot of ways of creating a problem though.

Andrew Bevin writes for Newsroom:

Ministers were warned of trade implications relating to mandatory Health Star Ratings before choosing to vote against the development of the scheme.

If Health Star Ratings are made compulsory by Australasian food ministers, and New Zealand manages to opt out, Australia would likely block imports of non-compliant food.

That’s according to advice given to the Cabinet Economic Policy Committee ahead of New Zealand’s vote against developing a mandated Health Star Rating system earlier this year.

If NZ made the FSANZ health-star ratings compulsory, Kiwi firms would have to comply. So would anyone else wanting to sell food in NZ. International outfits would then either eschew our market as not being worth the hassle, run limited production runs meeting the FSANZ standard (at higher cost both because of the smaller run and because they'd lose flexibility to shift products across markets as market conditions change), or make Kiwi retailers put stupid little stickers onto everything manually. 

All of those would limit competition here and push up costs. 

If NZ did not make the health-star ratings compulsory, Kiwi firms wanting to export to Australia would have to comply. And that's fine. They can do that. They could even sell the same version of the pack in NZ. And product from other countries could come in too - if they met our biosecurity standards. 

Why create another non-tariff barrier?