Battery cages for egg-laying hens are to be phased out under a new code of animal welfare released by the Government today.
But hens will still be able to be kept in larger cages known as colony cages, which may or may not give them outdoor access.
Under the new Animal Welfare (Layer Hens) Code of Welfare, released by Primary Industries Minister David Carter, no new battery cages can be installed by egg producers from tomorrow.
A staged phase-out of existing cages will also begin, with all battery cages to be prohibited by 2022.
''Scientific evidence and strong public opinion have made it clear that change is necessary. We need alternatives to battery cages,'' Mr Carter said.
Layer hens will be allowed to be kept in colony cages, which meet the requirements of the Animal Welfare Act, and in barn or free-range systems.
An immediate total ban on battery cages was not possible, as it would have an ''unacceptable impact on egg prices, industry structure and the stability of egg supply'', Mr Carter said.
''The phased approach balances the welfare of layer hens with the time needed for producers to transition to other systems.''
More than 80 per cent of New Zealand eggs are currently laid in battery cages, 'so this is a major shift for the egg industry and it needs to be handled appropriately'', he said.
Under the new code, about 45 per cent of battery cages will be gone by 2018.
The code was developed by the National Animal Welfare Advisory Committee (NAWAC), a committee that provides expert animal welfare advice to the Minister.
Committee chair John Hellström said the new code contains minimum standards and best practices to encourage the highest standards of animal husbandry, care and handling.
The code covers the full range of hen husbandry topics, including providing food, water and shelter, and protecting health.
''Battery cages house three to five hens and restrict hens from expressing a range of normal behaviours,''
Dr Hellström said.''
The new code will ensure that hens live in an environment that meets their welfare needs and lets them carry out a range of normal behaviours, such as perching, pecking and scratching.
''Under the new code farmers will be able to house their hens in colony cages or barns which may or may not give hens' access to the outdoors, he said.
''Colony cages are an acceptable option under the code because they allow hens to display a range of normal behaviours.
Colony cages are bigger, typically housing 40-60 birds, and include a secluded nesting area, perches and a scratching area.''
The code replaces the existing 2005 code of welfare for layer hens.