The group responsible for phasing out battery chicken cages within a decade has bowed to industry pressure and proposed extending the timetable.
John Hellstrom, chairman of the National Animal Welfare Advisory Committee, said there was "basically a stuff-up" when the Layer Hens Code of Welfare 2012 was introduced late last year.
Under the code, new battery hen cages will be banned and existing cages phased out by 2022.
Initially, the phase-out period was to begin in 2016, but the committee is now proposing to push this back to 2018.
Mr Hellstrom said this was because the industry had raised concerns that 2016 was too early and would create a significant disruption in the supply of eggs and a sharp hike in prices.
"We would prefer not to be making this change - we would have preferred to have had it better organised so that it was all done and dusted by the end of last year.
"If we had worked with industry more closely at that time we probably would have avoided it, but we were under a lot of pressure from animal rights groups and others not to be kowtowing to the industry.
"... It was basically a stuff-up."
Mr Hellstrom acknowledged the move would "reduce the welfare effect of the changes" but said it was necessary for the industry to meet the new standards.
"This is a big change that is going to cost the industry the thick end of $100 million. We have to take into account ... feasibility and practicality; how able they [the industry] are to make the changes."
The committee is seeking public consultation on the proposed changes to the code.
The committee is an independent body whose role is to give advice to Primary Industries Minister Nathan Guy on issues including the welfare of animals in New Zealand.
Eliot Pryor, campaign director for animal welfare organisation SAFE, said it was clearly a move that favoured business over animal welfare.
"It's disappointing. Battery cages should have been gone by now and to extend the timeframe ..."
"What always seems to happen is when there's a conflict between animal welfare and economic considerations it's always the animal welfare that is compromised."
Green Party animal welfare spokeswoman Mojo Mathers pointed out that, even when the changes were fully implemented by 2022, it was "nonsense" to say the industry would be cage-free.
"The changes they are proposing will replace battery cages with colony cages. That is not cage-free, and it is misleading to claim otherwise.
"We are going to be rid of battery cages but will just replace them with cruel colony cages - which are bigger but have many more chickens in each one, so hens will still be in cramped, confined conditions. Colony cages still don't provide chickens with anything resembling a good life."