The Alexanders have taken on the task of looking after several lambs at their home in the Auckland central city suburb of Ponsonby.

An animal that is usually seen by the thousands in paddocks dotted throughout rural New Zealand is becoming a novel pet in Auckland's most expensive neighbourhood – and even at one of the swanky suburb's more exclusive restaurants.

It's not just the sight of lambs being walked around Herne Bay on leashes that is attracting attention – it's what they are wearing. To prevent them "making messes throughout the house", the trendy new pets are being clad in baby nappies.

The new fad comes as Auckland Council updates its Animal Management Bylaw. Council manager Max Wilde says new controls will be introduced next month, requiring a permit to keep stock, such as lambs and sheep, in urban areas. "Each application will be assessed taking into account any potential nuisance issues that may result," he says.

Chris Skelton / Fairfax NZ Tracy Alexander feeds lambs Elmo and Milo in her kitchen.

Tracy Alexander and her husband live in Herne Bay with three children. They bought a lamb for their ten-year-old daughter Charlie on Trade Me to have as a pet and feed by bottle until it is time for weaning.

Tracy says putting nappies on her Charlie's lamb seemed like a sensible thing to do so it can be part of the family inside their villa and not defecate all over the carpet and polished rimu floorboards.

The lamb is called Elmo and, as Tracy tries to rearrange his leaking nappy, she says she thought her days of dealing with dirty nappies were over. "But now I use a couple a day on Elmo for morning and night time when he comes into the house. Sometimes I put one on but it leaks so I put two on – one on top and one below as that tends to work better."

Michael Bradley Andiamo restaurant in Herne Bay, Auckland.

Tracy was so delighted with the latest pet that she bought one for a friend's nine-year-old daughter, Poppy, in the next street as well. "My friends think I am mad but they are orphan lambs from a farm and I am doing this as a civic duty. It's nice for the kids at the same time."

Charlie describes having a lamb in central Auckland as fun, but wrinkles her nose at having to clean up after it. "Sometimes they do really sloppy poo and sometimes it is like marbles. They pee a lot! The other day we took the two lambs on their leads up to Andiamo and they got lots of attention."

Andiamo was quick to post a Facebook photo of Tracy with one of the lambs, at an outside table: "We are happy to serve anyone!"

Charlie says her school friends said, "oh my God" when they saw she had a nappy wearing lamb.

"But then they start laughing when they see us going for a walk and now some friends want a pet lamb as well."

Poppy's mum, Bridget, brings her daughter's new lamb down the street for play dates.

"We live up the road and every day I bring our lamb Milo over for a play date for the whole day. I usually feed them a few times a day. I see it as doing the farmers a favour and it is positive for our children as they have to feed them and it's a nice thing to do."

Her daughter Poppy scratches her lamb Milo behind his ears. She describes her woolly pet's personality as really cute. "He is very frisky and loves playing with you. The hardest part is cleaning up after him but it's just something I have to do."

Bridget says their friends think they are mad. "But on the other hand, they are happy for their children to come around and play with Milo, and their kids want a pet lamb too."

Charlie and Poppy understand that when the lambs no longer need to be bottle-fed and are ready for grass they will go to a farm.

Tracy Alexander with one of her urban lambs at the exclusive Andiamo restaurant in Auckland's Herne Bay.

But Charlie insists Milo and Elmo will not be going to the freezing works – and looking after a lamb has put them off enjoying roast lamb.

She says having a lamb made her want more pets and she has just asked her dad about it.

"I don't know why, but when I suggested we get a horse, a cow and a pig he said, 'Sure Charlie ... in a thousand years'."

Meanwhile Tracy is chasing Elmo around their small front lawn and grabs a sodden nappy that was stuck around his back leg. Charlie stands by clutching a couple of new nappies.

"I suppose it's like the opposite of a farm." says Charlie.