Light-fingered patrons are taking advantage of Wellington's switch from plastic straws to metal ones.
Last month a stretch of the city's waterfront from the train station to Freyberg Pool went plastic-straw free, meaning 26 restaurants, cafes and bars are now using alternatives or ditching straws altogether.
But the move away from plastic has created a new problem.
Shake milk bar owner Aston Christie said last school holidays more than 20 of his metal straws disappeared.
He said customers appreciated the effort to scrap plastic but unfortunately also liked taking the metal straws home.
"It's hard because on one side you're getting people who are taking these straws but they'll be using them elsewhere. They won't be using their plastic straws at home or other businesses, but they're not paying for them. So we're in two minds about it but at the end of the day we lose out."
Christie said it was amusing people assumed the straws came with the cost of a milkshake.
"We find it so bizarre because where do you go in a dining experience where the cutlery is included in the meal?"
Poquito co-manager Ryan De Dominicis said he was having a similar problem.
He said about 20 straws went missing a week and it cost about $10 for a pack of six.
"We will keep it up but it's disappointing and it would be nice if people actually thought about the reasons behind the metal straws and why we're doing it."
Charley Noble is in the same boat.
Restaurant manager Melissa Lind said about five go missing a week.
"We've had people steal salt and pepper shakers before, you have people steal tomato sauce bottles, but I guess it's just one of those things that you don't really have in the household and it's kind of a cool thing for opportunists to grab one."
"As it is a decision that we've made as a restaurant to turn to metal straws it's just like glassware, when it's smashed we've got to replace it."
Hospitality New Zealand general manager Rachael Shadbolt said it was a cost establishments would have to decide if they could continue to absorb.
"Sadly when you put something cool into the hands of the general public sometimes things walk away and I would imagine that those metal straws are actually quite desirable so there is going to be an element of loss when you're using the metal straws."
Wellington City Council sustainability portfolio leader councillor Iona Pannett said it was disappointing to hear straws were being stolen.
"To steal is against the law, it must be annoying for the businesses but I just think we should just start to learn to think about the way we drink a little bit differently and that's without a straw."
She said the answer was to stop using straws in drinks unless they were needed for a medical reason.
"You can drink them [milkshakes] without a straw, you can use a spoon. I just think this is one of the plastic uses which is pretty easy to replace."