A second egg brand has been caught up in the controversy over eggs sold as free range that may have been cage-laid.
Supermarket chain Countdown yesterday removed Palace Poultry brand free-range eggs from its shelves following the claims.
An investigation by the news service Newsroom concluded that many of the eggs sold to Countdown stores by Palace Poultry as free range were likely to have been laid in cages.
The Serious Fraud Office is investigating the allegations.
A second brand, Woodland, has now been caught up in the controversy.
Mainland Poultry managing director Michael Guthrie said his company's Woodland brand had supplemented its stock with Palace Poultry eggs.
Mr Guthrie said he thought the firm it was buying free-range eggs, so paid free-range prices.
"We've spent tens of millions of dollars building our business and Woodland as a brand.
"We don't want to undo it by two or three percent of what we may have purchased."
Woodland eggs stay on the supermarket shelf
Countdown supermarket said it would not pull Woodland eggs from its shelves.
In a statement, Countdown said Mainland Poultry's Woodland brand stopped using Palace Poultry eggs in early February.
It said it had recieved assurances from Mainland Poultry that their free range eggs were from verified sources.
Countdown said it would bring in an independent third party to review the traceablility of all free range and barn egg suppliers.
Consumer Affairs Minister Jacqui Dean said the government would not look into the idea of compulsory labelling of eggs because it would be difficult to enforce.
Ms Dean said the best way to deal with the issue was to ensure the Fair Trade Act was properly enforced.