KEY POINTS:
Police are continuing to investigate possible sightings of missing Cromwell woman Jessica Roberts, who had apparently picked up a hitchhiker on the last day she was seen.
Ms Roberts picked up a hitchhiker near Wanaka about 1pm on Saturday but he became concerned about her slow driving and behaviour, bailing before reaching Fox Glacier, Constable Peter Jeffreys, of Greymouth said.
"She was driving quite erratically, so he ended up getting out before arriving in Fox Glacier," Mr Jeffreys said.
The hitchhiker had thought she was not quite right, the Southland Times reported.
She had not told the hitchhiker where she was going, Mr Jeffreys said.
Ms Roberts has not been seen since last Saturday night when she pulled up her Nissan Cefiro saloon car at the Fox Glacier petrol station to make a phone call and buy cigarettes.
But she was turned away because she had lost her Eftpos card and had no money. She was earlier seen driving erratically near Franz Josef Glacier.
Police said concern for her safety was growing daily because she had had mental health issues and recently reduced her medication.
Police have now searched State Highway 6 from Makarora to Harihari, checking for Ms Roberts' car at accident danger spots.
Mr Jeffreys said the police road sweep would not continue, but further sightings were still being investigated.
Fearing Ms Roberts may have run her car off the road, her father, Rian, hired a helicopter to search the main highways in the region, but no sign of her or her vehicle has been found.
There was an unconfirmed sighting of her in a car in a layby near Hokitika on Sunday. A pillow found on the side of the road was collected by police who are yet to confirm whether or not it belonged to Ms Roberts.
A Haast Police spokesman said yesterday flyers had been distributed around the West Coast and officers would remain on the lookout over the weekend.
Ms Roberts was believed to be wearing dark blue trousers, a lime green singlet-type top with a symbol on the front, either a cream or green cap, red rimmed glasses and a thin, knee length black and white chequered coat.
She is described as European, 175cm tall, of medium build with brown curly hair. Her car's registration is UH9394.
- NZPA