More than 1500 children will be recalled to have their hearing checked by Hawke's Bay District Health Board.
They may have been incorrectly screened as part of the Newborn Hearing Screening Programme is finalised.
Paediatric clinical director Philip Moore said the 1524 figure was made up of 747 children who
had been screened since 2008 and identified from the audit as not having been screened correctly.
The additional 777 were babies who had been born in the past six months.
"We have been overly cautious and are recalling all babies screened in the past six months as well, as we can't say for sure that they have been correctly screened," Dr Moore said.