Pets are now allowed on Auckland's trains, including dogs that are wearing muzzles.
Auckland Transport carried out two trials of pets on trains, the second one ending in March, and decided to make the move permanent.
A leading advocate for the change, Councillor Cathy Casey, said it was an important step toward making Auckland a more dog-friendly city.
She hoped dog owners would be responsible and keep their pets on leash when traveling on trains.
Next on her list was getting dogs to be allowed on buses.
"It's about building that confidence that dog owners do know what they are doing.
"I want people to like my wee dog, and I've found when I do travel on the train, people really like it."
An Auckland Transport survey last year found just 12 percent of people were opposed having pets on trains.
Stacey van der Putten, group manager of metro services, said customers had enjoyed being able to take pets on trains.
"Pet owners have been very supportive of the protocols that have been put in place to allow this initiative to happen."
Pets can go on trains on weekdays 9am to 3pm and after 6:30pm, and all day on weekends and public holidays.
All dogs must either be wearing an approved muzzle and lead, or be travelling in an approved pet carrier.