Adoring female fans may have struck Christchurch mayoral candidate Nathan Ryan's billboards again. Two have been stolen and four others vandalised in recent days.

Ryan, 38, was something of a pin-up boy during the 2007 election when female fans made no secret they wanted his billboards. But it isn't so novel this time.

"I was in complete shock. I can't understand why they would steal the image off the billboards, I am 38 years old for gods sake ... I am not Justin Bieber," Ryan told The Press this morning. The most daring act took place outside his home at 1am yesterday.

"I heard a ripping sound outside this morning and when I went out someone was ripping my head off the billboard of my own fence."