Cases in Wellington and Auckland have tripled in the past three years, TVNZ said Friday.

There were 60 new cases of infectious syphilis in Auckland and 15 in Wellington in the last six months of 2006.

The disease, which can cause insanity and death, has been easily treatable since the 1940s, but some people don't have any symptoms and don't know they need to seek medical attention.

The outbreak mirrors trends in other countries and has predominantly struck young gay men.

Heath officials said they are expanding their awareness campaigns, increasing testing and encouraging safer sex practices, TVNZ said.