Dogs of all sizes will be able to travel on trains in Auckland from Sunday.
Auckland Transport said that, previously, only dogs small enough to fit inside a carrier were allowed on-board.
But it's extending its pets on trains trial and now all dogs will be able to travel, as long as they are wearing an appropriate muzzle and leash.
Metro Services group manager Stacey van der Putten said the trial allowing small dogs had gone well and expanding the trial would benefit more owners and their dogs.
Auckland councillor Cathy Casey said it will allow dog owners to get out and about, using public transport.
"The relaxation of the requirements means that more dogs will be able to join their owners on the train for days out and errands without needing a car.
"This is another step towards making Auckland a dog friendly city where pooches are integrated into the life of our people and welcomed onto all public transport like they are in many of the great European cities."
There are 106,000 registered dogs in Auckland.
Dogs will only be allowed to travel at off-peak hours - (9am - 3pm and 6:30pm until the end of service on weekdays, and all-day weekends and public holidays).
The trial will run until March.