Key Points:

A German tourist has been raped at knifepoint at a scenic reserve near Raglan, barely five weeks after the vicious kidnapping and rape of a Dutch couple in Northland.

The attack happened on a walkway at the Te Toto Gorge Lookout scenic reserve, between Raglan and Ruapuke, on Friday.

The woman, 43, was on the second-to-last day of a six-week holiday in New Zealand and was by herself at the time of the attack.

She has since returned to Germany.

The rapist struck on the walkway about five minutes' walk from the reserve carpark.

The rape is the second horrific crime against a German traveller in the past 15 months.

Backpacker Birgit Brauer was abducted and murdered in September last year.

On Friday, the German visitor parked her rented vehicle, a grey Suzuki Swift, in a carpark before setting off on a walk on a fine, clear and hot day.

She was in a secluded area, about five minutes into the tramp, when a man with a knife approached her from behind, police said.

It is understood the man had acted alone and police were yet to gain any strong leads. The woman alerted police after the attack by driving to the Raglan station.

Detective Sergeant Michele Moore said the attack happened between 3.30pm and 5pm. She was keen to speak to the occupants of two cars that were in the carpark before and after the attack.

"We believe there are at least two groups of people who may have seen the woman in the reserve area during the afternoon," Ms Moore said.

"They may have also seen the attacker. It's vital that we speak to them as they could have important information that would help us find this man."

The gravel road on which visitors to Te Toto Gorge reserve would have travelled was windy and narrow, and vehicles needed to slow down to pass one another.

Surfers and fishermen in the area might have witnessed suspicious activity or the vehicle police were seeking, Ms Moore said.

It was unknown whether the man was a local or a visitor to the area.

A Wellington spokesman for the German consulate, Tilman Enders, said a travel advisory warning German nationals against travelling alone in New Zealand would not be issued.

"This is a tricky case. That [crime] can happen anywhere at home.

"People travelling are probably aware that this can happen anywhere abroad."

Tourism Industry Association chief executive Fiona Luhrs did not think things were "at a level of concern that would turn people off coming here" despite the recent attacks against tourists.

"New Zealand is still a safe destination compared to many other destinations - in fact, most others," she said.

The generally laid-back attitude of New Zealanders and the country's relaxed atmosphere could mean some tourists were not taking the necessary precautions when coming here, Ms Luhrs said.

"Some do get to New Zealand and think people are so nice and friendly and they might not need the same kind of alertness they need when in a place like London or New York."

THE SUSPECT

* In his 40s, athletic build.

* Short blond or grey hair, olive skin.

* Driving a large, pale-coloured old-style sedan.

- Additional reporting by James Ihaka