Dunedin City Council records show there are now almost 3000 more dogs in the city than five years ago - an increase of 21.5%.
Human population growth has been sluggish by comparison with just 0.8% average annual growth at the last census (2006) for Dunedin.
Animal Attractions owner Judi Johnson said she had noticed a trend towards more people buying two dogs over the past three or four years.
The average price of puppies had declined from about $1100 three years ago to about $600 today, which could have contributed to the increase, Ms Johnson said.
"It's almost as affordable for people to have two dogs these days," she said.
Pet Palace retail manager Donna Donaldson said she believed the increase in registered dogs could be put down partly to cheaper puppy prices, and partly to the council collecting more information about dog owners.
"The council is now aware of who buys a dog and where. All those records are kept.""They have their finger much more on the pulse now," she said.
Council environmental health and animal control manager Ros MacGill said the number of dog owners had not increased in proportion to the number of dogs.
"It seems to be more popular - people having two or more dogs these days - rather than just the one," Ms MacGill said.
The DCC has eight dogs listed as "dangerous", compared with 12 dangerous dogs last year.
A further 75 dogs were classified as "menacing" because their behaviour had come to the attention of the council and 149 dogs were considered "menacing by breed", she said.
Ms MacGill said the number of "menacing by breed" dogs, which were mostly pit bulls, was expected to decrease over time because people were no longer allowed to breed them.
Council records show Dunedin's dog population was 16,235 as of June 30 this year.
Ms MacGill said 15,024 were registered and 1211 dogs were unregistered. Their owners would have to pay a late registration fee of $132 - 50% more than the standard $88 fee.
