Police have accidentally shot a Hastings man in their custody.

The 33-year-old man was shot when a police firearm "accidentally discharged" towards the man, who was in custody and lying on the ground, said acting assistant commissioner investigations Glenn Dunbier.

Police were called to a house in Karamu Rd, Hastings around 5pm after concerns about the behaviour of the man, who had pointed a firearm at his mother two days ago.

Family rang police this afternoon after concerns about his behaviour.

The man was taken immediately to hospital by ambulance. A hospital spokesperson later said the man was in a critical condition.

Dunbier said two investigations into the shooting were underway by police and the Independent Police Complaints Authority.

Police were speaking with the man’s family this evening.

"This is a very serious event that police will be looking into thoroughly. We will be interviewing everyone who was at the scene at the time of the incident as part of our investigations.

"Our thoughts are with the man and his family at this time and we will be liaising closely with them," Dunbier said.