One firefighter's missing and a second is critically injured after a landslide wiped out a home in Auckland's Muriwai

A volunteer fire brigade crew was investigating flooding in a house on Motutara Road when a landslide happened on the slope above and the house collapsed.

Two firefighters were trapped, with one rescued early this morning.

The search for the second is suspended due to the instability of the land.

A full rescue operation began as soon as the landslide hit, involving 10 crews from seven brigades and including Urban Search and Rescue, Police and St John.

A geotechnical assessment of the area will be carried out as soon as possible so decisions can be made about resuming the search.

Residents of two roads in coastal Muriwai were told to evacuate about 1am after a landslip blocked Motutara Road and two homes collapsed.

Auckland Transport says flooding on Seaview Road and Piha Road in Piha have caused the area to be blocked off, along with the beachside area of Karekare.

Fifty apartments in Mount Eden have been evacuated during the night due to fears the historic Colonial Ammunition Company Shot Tower might collapse.