Twenty years on the run from immigration officials will end when Jurgen Karl Ahrens is deported this morning.

The 72-year-old German overstayer was arrested on Thursday in the Aoraki/Mt Cook National Park after being spotted by the public.

He was wanted by police on a charge of assault at Fox Glacier in 2004 and after being arrested, appeared in the Timaru District Court before being transferred to the Christchurch courts yesterday.

After his appearance he was remanded in custody, where he was to remain until immigration officials deport him to Germany today.

Twizel police constable Joe Rush spent time with Ahrens after his arrest.

The scruffy-looking man was not perturbed at welcoming 2011 in at a Twizel police station cell, telling Rush: "This is an interesting part of my life."

Ahrens was fit – a keen tramper, climber and kayaker.

At the station Ahrens was relaxed. With long, straggly hair, unshaven and unshowered, he wore a long-sleeved cotton shirt, brown trousers and old shoes.

"If you saw him you would think he's a bit of a rough bugger."

However, his appearance belied his manner, Rush said.

"He just constantly talked," he said.

"He speaks English well, he was very polite and was quite easy to talk to."

Ahrens showered at the police station and had a cup of tea. He said he lived in a flat in Christchurch's Linwood suburb, rented from a friend in Auckland. His money supposedly came from his German pension.

Ahrens claimed to have come to New Zealand from Australia where he had worked for 20 years. It was a lie, Rush said.

His German passport showed he came from the Philippines.

"He didn't really say why he came here. He claimed he had some investments in the North Island."

He was asked about the Fox Glacier incident that led to the assault charge. Ahrens had been living in a flat in the town at the time.

"He declined to comment about it."

His relaxed manner after the arrest was strange, Rush said.

"I found it quite odd," he said. "If I was arrested and knew I didn't do it, I would be kicking and crying blue murder."

Until his arrest Ahrens got about in a 1980s Mercedes with his kayak on the roof. He got a New Zealand driver's licence in 2000 and had never had a parking ticket or a speeding ticket and had never come to police attention – other than at Fox Glacier.

Ahrens had said there would be no family or friends waiting for him on his return to Germany, though Rush said it was difficult to know if that was the truth.

Certainly in New Zealand he seemed to be a loner, Rush said.

On the journey to the Timaru police station, Ahrens recalled parts of the district he had stayed in, areas such as Hanging Rock.

He had a sound knowledge of South Island geography, especially Department of Conservation land, and claimed to have been visiting Aoraki/Mt Cook for about 15 years.

When police finally caught up with him, Ahrens had been using a different name, apparently because he got tired of being asked how to pronounce his surname.

Tekapo police senior constable Brent Swanson said that Ahrens' car was his downfall.

"It's the third year now his vehicle has come to our attention and each time he slips off the radar and disappears."

Swanson said it was "pretty good work" by the public that led to Ahrens' arrest.

"The only thing that was his downfall is he kept the same car, an old Mercedes. If he had been driving some old nana's car no-one would have noticed."

A witness, who declined to be named, said police had previously asked people in the national park to keep a look out for an elderly man in an old Mercedes Benz.

On Thursday morning he was seen paddling on the Tasman Lake.

"The kayak he was in was pretty old, it was pretty ancient gear."

While Ahrens will be gone today, Interpol and other agencies will continue to investigate his 20-year expedition, Rush said.

(Source The Press)