The Dunedin City Council has contacted 400 dog owners about unpaid registration fees and is now sending some dogs to the pound.
Local charity Dog Rescue Dunedin said it was hoping people would get their dogs registered because if too many were impounded it could cause a strain on the charity's resources.
Animal Control team leader Ros MacGill said four dogs had been removed from owners' properties last week. One owner had since paid what was owed and taken their dog home again.
''We started with about 400 dog owners that we were visiting and we are down to about 200 now, approximately,'' Ms MacGill said.
Dogs are kept in the pound for six days to allow time for owners to retrieve them, after which they are offered to Dog Rescue to re-home, for a cost of up to $100.
Dog Rescue manager Jo Pollard said they had been putting posters up all around the city to encourage people to register their dogs.
They were also trying to recruit more foster homes for the dogs they did rescue.
Ms MacGill said owners had had four months to register their dogs and council staff had been working hard to remind owners of their responsibilities.
''We have given them ample warning and opportunities to do that so if they still choose not to work with us and get their dog registered, there is a risk that we will remove that dog and impound [it].''
Dog Rescue was set up in 2011 to save, desex and re-home unclaimed pound dogs because any dogs that cannot be rescued from the pound are eventually put down.
Ms Pollard said the trust had also extended its range of foster homes to South Canterbury, in the hope of saving more dogs.
