10am update:  The Thames Coast Road has now reopened following a crash earlier this morning.

NZTA Waka Kotahi have confirmed that State Highway 25 between Kereta and Tapu is now open.

Emergency services were alerted about 3.25am, after a car reportedly hit a power pole and crashed into the water near Russek Road.

It is still unknown at this stage if there are any injuries.

Over 15,000 visitors are expected to attend the Keltic Fair in Coromandel Town today, which runs from 9am - 4pm. Travellers had been advised to consider detouring via SH25a while SH25 remained closed.

SH25 is now open.

Thames Coast Road. Photo: Rosalie Liddle Crawford/SunLive.

9am update:  State Highway 25 is still closed between Tapu Coroglen Rd and Manaia Rd Saddle and Lookout due to a serious crash.

Emergency services were alerted about 3.25am, after a car reportedly hit a power pole and crashed into the water near Russek Road.

NZTA Waka Kotahi advise considering detouring via SH25A as SH25 is closed until further notice.

For further information please check the Highway Conditions Map here: http://spr.ly/6187R5xKh

Earlier, 5am: A serious crash has closed State Highway 25, Coromandel.

Police are at the scene of a serious single-vehicle crash that has closed Thames Coast Road south of Kereta.

Emergency services were alerted about 3.25am, after a car reportedly hit a power pole and crashed into the water near Russek Road.

State Highway 25 will remain closed for several hours.

There are no detours available, anyone needing to travel to or from Coromandel will need to go via Whitianga.

NZTA Waka Kotahi say the road is closed until further notice.

Motorists are advised to delay travel or allow extra time for long detours.

The Serious Crash Unit is investigating.

At the scene?

Phone 0800SUNLIVE or email newsroom@thesun.co.nz