A smoke alarm call-out to Sir Peter Jackson's Wairarapa mansion has baffled firefighters, who discovered a mysterious mist inside the house.
Firefighters attended Sir Peter's property at Matahiwi near Masterton at 6pm yesterday after smoke alarms were activated.
Masterton station officer Garry Nielsen said when they arrived at the three-storey house they found a mist-like haze in the property's upper story.
''We could certainly see something but we couldn't determine what it was,'' he said.
''It wasn't really like smoke, it was more of a mist actually.''
The house was ventilated by firefighters to disperse the haze, and its cause sought.
''We couldn't find anything,'' he said.
''It was unexplained, I don't think we'll ever know what caused it.''
No-one was home at the time, he said.
Sir Peter and partner Fran Walsh bought the 37ha property in 1998, and it now features a lake, railway and a castle.
The couple have since transformed the house into a two-towered mansion complete with indoor pool and 100-seat cinema.