The SPCA is commissioning more research into whether domestic cats are killing native birds.
A bitter spat between the animal welfare organisation and Gareth Morgan is continuing, after the economist last week launched a campaign to reduce cat ownership.
Mr Morgan called for cats to be desexed, registered, micro-chipped and kept inside to try to preserve native birdlife.
The SPCA maintains its research showing domestic cats are not the main killers of native birds is still accurate.
President Bob Kerridge says it is commissioning more research so New Zealanders can be assured the "loopy" comments by Mr Morgan aren't true.
Mr Kerridge said it will study the felines' habits and analyse research on their diets.
The research, some of which will be paid for by the SPCA, will be released in a couple of months.
In the United States, newly published research has suggested cats are one of the top threats to US wildlife, killing billions of animals each year.
Scientists from the Smithsonian Institute estimate cats are responsible for the deaths of between 1.4 and 3.7 billion birds and 6.9-20.7 billion mammals annually, the BBC reports.
The authors said stray and feral cats were the worst offenders but added pet cats also played a role and that owners should do more to reduce their impact.