More than 3300 dogs impounded in Auckland were destroyed in 2010-11 after being unclaimed by their owners and deemed too dangerous to be adopted.
Only 670 dogs were given to new homes, according to Auckland Council figures for the year to July, and one in three seized animals was put down.
Owners have one week to claim an impounded dog from the council before it is tested for aggressive behaviour and ill health, and whether it should be classified as a menacing breed.
Those deemed unsuitable for a new home are put down. But one animal advocate says the low number of adoptions is partly because people don't like "ugly dogs".
"Most people will be appalled at the dogs being killed and expect us to do a lot better in finding new homes for them," said Dr Cathy Casey, the Auckland Council member who obtained the figures.
She said council officials should work harder to get more dogs adopted and cited overseas dog control authorities which allowed people to look at impounded animals and choose one to take home.
"Auckland's pounds are off limits," Dr Casey said.
She said people did not want to adopt ugly dogs.
"The adopted ones tend to be more beautiful and younger, so if you are older and uglier you have less chance of being rehomed.
"Dogs are being killed unnecessarily. They would make good companions."
Dr Casey said people should be able to look on the council website to find a dog - and senior compliance officer Ian Parker said this would be possible in a few months.
Mr Parker said that while looks were a factor in adoption choices, most destroyed dogs were unsuitable for adoption for other reasons, such as their aggressive nature, health or they were of a breed classed as "menacing".
Some dogs deemed unsuitable for adoption were placed with government and civil defence agencies for training in customs and agriculture border control, as well as police work.
In South Auckland during the past year, 171 dogs went to the SPCA, police or a breed club.
Mr Parker said the council did not know how many dogs deemed suitable for adoption were put down.
However, of the 144 dogs put down in West Auckland between July and October, 31 per cent were deemed suitable for adoption.
Mr Parker said dogs must be kept for seven days at the city's pounds so owners to claim them. But the animals were held longer to allow for temperament testing and to give staff more time to find the owner.
The Auckland SPCA, which is funded by donations, found new homes for 686 dogs and puppies in 2010-11 but was unable to say how many it had to put down.
The Auckland Council adoption fee is about $250 for puppies, which includes vaccinations, registration and neutering, and $195 for older dogs.
Auckland Council believes the region has about 105,000 dogs, but only 97,471 are registered.
Auckland dogs destroyed in 2010-11 compared with number adopted:
Central 535 (76 adopted)
Manukau 1754 (174)
Franklin 147 (49)
Papakura 258 (39)
West 458 (196)
North 186 (137)