Several loud bangs have been heard at a house surrounded by armed police in Christchurch tonight.
About 20 police officers have been outside the house on Gilberthorpes Rd, Hei Hei, for several hours.
A witness says he heard a couple of bangs - possibly stun grenades - go off in the house around 6pm and several more around 8pm.
He says officers have put gas marks on and "look like they're about to storm the house".
The witness says officers are now on the property and have been using a loudspeaker to warn whoever is inside the house that they're going to come in.
The police have said officers had a "pre-planned search warrant".
They would not comment on whether that search warrant was related to the fatal shooting of Luke Riddell at Charing Cross on Saturday.