Dunedin boy (2) in car 'at 170kmh'

A Dunedin toddler was a passenger in a car which allegedly reached speeds of 170kmh during a police pursuit on Wednesday, police say.

A 30-year-old Amberley man picked up his 2-year-old son from the boy's daycare facility in Dunedin about 2.30pm, as agreed with the boy's mother.

However, instead of returning the boy home the man began driving towards Christchurch, Southern District Command Centre deployment co-ordinator Senior Sergeant Brian Benn said.

Police were contacted by the child's 26-year-old mother about 5pm.

She was concerned about the boy's welfare, Snr Sgt Benn said.

Dunedin police were able to contact the man on his cellphone and he told them he was driving towards Christchurch. Dunedin police then contacted Christchurch, Snr Sgt Benn said.

There were no family court orders in place before the incident, he said.

Senior Sergeant Malcolm Johnston, of Rangiora, told an online news website that the man was seen by police north of Christchurch about 7.30pm. He was allegedly driving about 170kmh.

The man threatened to harm himself, and police had concerns for him and his son, he said.

Police followed the car at a distance and arrested him at the house of a family friend in Amberley, he said.

''We were just thankful that they arrived safely ... The driver was incredibly unpredictable and wound up to the point that we didn't want to put any more pressure on him at all,'' Snr Sgt Johnston said.

''It had the potential for a real tragedy.''

Snr Sgt Benn said the child was unharmed and had been reunited with his mother.

The man was served with a five-day police safety order after the incident, he said.

The man will appear in the Christchurch District Court on on July 19 on charges of dangerous driving.