A man who sexually assaulted a 17-year-old girl in Onekawa early Sunday morning had approached and threatened her with a steel spanner before the attack, police have said.

The man forced the teenager into a public toilet block off Maadi Rd, opposite the Onekawa shopping centre and attacked her. Police recovered the spanner from the scene and it was being forensically examined.

Detective John McGregor of the Hawke's Bay CIB said the attack happened about 1am as the girl was walking home. While she received no physical injuries she was left emotionally shocked. Detectives investigating the incident left it until yesterday to conduct a detailed interview with her.

At the centre of the investigation is the report of a man seen walking around the shopping centre in the time before the attack. Mr McGregor said the man was on his own, and his behaviour caught the attention of one member of the public who had seen him.

"He appeared quite agitated and we want to hear of any sightings of this person, who was hanging around the shops between 11pm and midnight."

Described as Maori, aged about 18 with long dark hair, he was wearing jeans and a blue checked top. Mr McGregor said he also appeared to have a bandanna, or an article of clothing like a T-shirt, wrapped around his face.

"There would have been some traffic on the road at that time and it is important we talk to anyone who was driving through or perhaps walking in the area at the time."

Napier Mayor Barbara Arnott said the incident was unsettling but served as a warning.

She said Napier was as safe a city as any but young people out at night needed to ensure they had companions with them.

"Of course people should be safe and feel safe in our city, but young people need to be with company, with friends."

She said for a 17-year-old to be out on their own at that time of the night was not wise and that young people going out needed to ensure they were not out alone.

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