A serious crash in the Coromandel has injured two people, brought down power lines, and closed State Highway 25.

Police say a vehicle collided with a power pole at 11.55am between Timata Rd and Woody Hill Rd leaving one of the occupants critically injured and another seriously injured.

SH25 has been closed at Pukepoto while the serious crash unit investigates.

SH25 is also closed between Coromandel township and Matarangi due to slips. Motorists should expect delays, and delay travel if possible, police say.

Earlier, Auckland motorists were struggling with two separate crashes on SH1 this afternoon - including an accident that left all southbound lanes blocked on Auckland’s Harbour Bridge.

A crash occurred about 12.30pm north of the harbour bridge on SH1 after Shelly Beach Rd off-ramp heading southbound.

Waka Kotahi NZ Transport Agency warned motorists to expect delays and to pass the crash scene with care.

Another accident on SH1 in the Auckland region this afternoon blocked traffic just south of the Drury off-ramp.

Due to a crash after the Drury Off-ramp, the northbound lanes were blocked. Photo / Jim Burchall

There was only one SH1 northbound lane clear after the accident in Drury which disrupted northbound traffic from Ramarama to Papakura.

The accident occurred at 12.50pm and the transport agency had told motorists to expect significant delays.