POLICE were investigating today after petrol was poured over the front door of a house and set alight.

Forensic experts and fire chiefs were called to Pine Street, Nelson, following the incident at 8.50pm yesterday.

Detectives said they were treating the arson attack as a serious incident.

People in the house at the time raised the alarm after they heard liquid being thrown at the front door.

Police said when they went to investigate, the front door was ablaze.

The residents managed to extinguish the flames by throwing a washing-up bowl of water at the door.

Sub officer Mark Woodward, said: "We got the call as persons trapped in the house but by the time we got there they had managed to extinguish the fire.

"Severe damaged was caused to the front door. It was lucky the occupants were not in bed because the fire could have spread.

"This is a very serious incident which we will be working with the police to investigate."

A police spokesman confirmed that they will be investigating the incident.

Two people, who did not wish to speak about the ordeal today, were treated by paramedics for shock.