The search for a missing man in the water at Lake Tekapo will resume this morning.

Emergency services were called about 8pm on Thursday after reports that a man had entered the water and failed to resurface.

Senior Sergeant Hamish Keer-Keer said sadly the man has not been located.

Police search and rescue staff, along with Coastguard Mackenzie Lakes volunteers, Fire and Emergency New Zealand, and a helicopter, were all deployed and conducted a search in freezing conditions.

A local Coastguard volunteer with his own private vessel, alongside a police officer, began an initial search before the Coastguard Mackenzie Lakes crew arrived.

A Coastguard spokeswoman told Chris Lynch Media on Thursday night the crew was at the scene and actively searching under the lights of a supporting rescue helicopter.

Volunteer rescue personnel at the scene told chrislynchmedia.com they were searching for a person reported missing in the river.

A rescue helicopter had been scouring the river and lake, while a Coastguard rescue boat searched the water and the banks alongside Fire and Emergency crews.

A Fire and Emergency spokesperson said they were called by police to assist the search, but police was the lead agency.