An armed man is believed to have taken two children hostage at Waihi.
Police said they were searching for a blue Toyota Surf SUV being driven by a man with a female passenger and two young children.
The man is believed to be armed.
TV3 reported the man had taken two children hostage.
"Certainly people shouldn't approach the car,'' Thames-Coromandel Senior Sergeant Graham Shields said.
"Every single police officer we've got in the Coromandel and Hauraki area is out searching for this car right now.''
Inspector Dana McDonald said concerns were raised about the car in Cambridge about 2.20pm.
"We've had an unconfirmed report of the vehicle in the Waihi area and Police from across the Waikato are working with Bay of Plenty colleagues to try and locate it,'' Ms McDonald said.
"If members of the public sight the vehicle they are asked not to approach the vehicle but to ring 111 immediately.''
