Builders helped an English tourist left "bruised and bloody" in an alleged sexual attack on a walkway overlooking Owhanake Bay on Waiheke Island.

A building company owner working at the gated Delamore Estate said the woman, aged 29, came to the driveway at 3.30pm yesterday asking for help.

"I did a double take. Her face was bruised, bloody and purple," he said.

"We took her in the garage, sat her down and gave her water while she phoned the police.

"I called to a couple of the boys to come down. They rushed down the track but couldn't find the attacker so they came back."

One builder drove around to Korora Rd and down to Owhanake Bay where the track ends. Another went with the police in the same direction shortly afterwards.

"The police eagle helicopter was on the scene within five minutes," the builder said.

Cane Norton Kelland, 17, appeared in Auckland District Court today facing one count of sexual violation and injuring with intent. 

The victim arrived in the country on January 21 and was on a day-trip to the island, Knight said. She is now in Auckland.

Knight assured people the island was safe but said common sense should always prevail.

"This is a one-off but it is always safer if you walk in groups or go out in groups at night."

- © Fairfax NZ News