An animal welfare campaigner says a proposed code of welfare for layer hens breaches the law and should be re-drafted.
Barrister and campaigner Catriona MacLennan says a move from battery cages to colony systems, which would allow each hen an extra 200 square centimetres of space, breaches the Animal Welfare Act.
She says it fails to allow hens to display normal patterns of behaviour like dust bathing and walking freely.
The draft code by the National Animal Welfare Advisory Committee recommends that the cages used by most egg producers be phased out and converted to the enriched colony systems.
Ms MacLennan says the committee should discard its draft code for layer hens and start again.
Nearly 90% of the country's eggs are produced by hens in cages, while the rest come from barn and free-range systems.
Submissions on the code closed on 29 April.