"Our experience is that cats who are properly looked after [neutered and fed] do not kill birds."
Other readers said cats controlled pests like rats and mice, and the real threat to birdlife was herbicide, agricultural chemicals and humans themselves.
However Forest & Bird has said the campaign, while provocative, highlights a serious issue that needs to be addressed.
Advocacy manager Kevin Hackwell said responsible dog ownership had been highlighted in recent years, and the same needed to happen for cats.
That included neutering cats, keeping them inside as much as possible, and fitting a bell to their collar - shown to reduce by half the number of native birds killed by domestic cats.
Mr Hackwell, a cat owner himself, said his Wellington family were giving serious thought to making their current moggy their last.
University of Otago research showed domestic cats killed at least 1.1 million native birds a year, he said.
"It's not insignificant ... no matter how well you feed them, they still want to come and show you the bird they have caught. There's no question that cats have an enormous benefit as companion animals ... I own a cat, I like cats ... but I am aware of the damage they do."
Rosalie Rainbow, the president of the Auckland Cat Club and a West Auckland cattery owner, said the campaign would have little impact on cat numbers.
"People that do get them do have a passion for them, and they are very good company. Because I live in Waitakere, you do worry about them getting into the bush, and all my kittens get desexed because of that reason," she said.
"But out of all the birds, they more hit your bloody windows than the cats getting them."
What the campaign wants
* Current pets to be kept in 24 hours a day.
* All cats should be chipped, registered and neutered.
* Families should not replace pets that die.
What the campaign claims
* One cat kills an average of 65 animals a year.
* They can range an area equivalent to 67 rugby pitches.
* They kill for fun.
garethsworld.com/catstogo
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Peter Calder: Morgan puts cat among the pigeons
Are cats too much of a threat to native wildlife?