Splash - the buildings can hit back

Cartoon / Rod Emmerson

Late-night drinkers beware - a new device will blast cold water on anyone who urinates against a building or tries to sleep there.

The system has been described as "obscene" by Auckland City Mayor John Banks, who once spent time sleeping rough.

Mr Banks said he did not believe public urination was a problem in Auckland City, but took the chance to have a dig at North Shore Mayor Andrew Williams, who has refused to deny claims that he urinated against a council building after leaving a bar.

"I've never seen a homeless person with a public urination problem," Mr Banks said. "I see it with public officials but I don't see it with the homeless."

Tony Bicknell, director of operations for Hasting-based Graffiti Security Systems, said he designed the Storm Door system after being approached by an Auckland firm that had a problem with homeless people and drunks urinating in its doorways.

The system had been installed in the National Bank Tower building in downtown Auckland.

"[The customer's] big problem was that they were having to send in cleaners ... There's not many ways you can stop people peeing in doorways or sleeping in doorways."

Mr Bicknell said the smell of urine was "absolutely putrid".