Police have closed a road south of Auckland after a serious crash this morning.

Emergency services were called to a two-car crash at the intersection of Kaihau and Awhitu roads, near Waiuku, about 9.35am.

A police spokeswoman said three people were injured in the crash.

"Two of these people were trapped in a vehicle for a time," she said.


"One has critical injuries, two have serious injuries."

"The Serious Crash Unit will be investigating and the road is closed, diversions will be put in place," the spokeswoman said.

Both of the Auckland Westpac Rescue Helicopters attended the crash.

Spokeswoman Kerrie Spicer said it happened about 4km from Waiuku.

One crew airlifted a middle aged woman to Middlemore Hospital in a serious condition.

The second crew took a young boy to Starship Hospital in a critical condition.

St John Ambulance transferred the remaining patient, a man in a moderate condition, Middlemore Hospital.