UPDATED 9.56PM

The search for a man missing in the surf at Muriwai Beach on Auckland's West Coast has ended for the night.

Life guards who were on the water in boats called off their search earlier, and a short time ago the helicopter was stood down until morning.

Another man rescued by life guards earlier was flown to hospital by Westpac rescue helicopter in a serious condition.

In another incident on the same beach, a man was seriously injured in a crash on a dirt bike and was also flown to hospital by Westpac Rescue Helicopter.

Police say another bike may have been involved in the crash, but they are investigating to establish that. They've taken two bikes and some witnesses to the Kumeu police station.