An Auckland Rescue Helicopter has been scrambled to Waiuku after a crash trapped two people.

Westpac 2 was currently on their way to the location south of Auckland city, Auckland Rescue Helicopter Trust spokesman Lincoln Davies said.

There is also a crash in Auckland city, on Pakuranga Highway, heading west towards the Waipuna Bridge.

It was causing delays in both directions, the New Zealand Transport Agency said.

Davies said the helicopter crew had just returned from a callout in Helensville at 1pm before being called to Waiuku.

The team had assisted a woman who came off the back of a ute north of Auckland.

"She suffered multiple head and leg injuries and was flown to Auckland City Hospital in a serious condition."

Earlier today, around 11.14am, crew were also tasked to help a man who had suffered a fall in Matakana.

"He was flown to Auckland City Hospital in a moderate condition."