Gellert Csaba Mudra (41), a Hungarian, was last seen paddling a hired kayak on the lake about 4.45pm last Friday.
Detective Sergeant Grahme Bartlett, of Queenstown, said divers yesterday had searched the bottom of the lake to rule out items picked up by sonar equipment in the 16.3m-deep bay.
A helicopter had also conducted an aerial search of the area and 30 volunteers had spent the day searching the shoreline.
The land search would be scaled back today, but the dive team would continue searching the Frankton Arm of the lake. Police say they are also keen to speak to another kayaker, who was in the Queenstown Bay area near the Botanic Gardens between 4.30pm and 5.30pm last Friday.
Det Sgt Bartlett said a woman had told police she saw a man park a dark-coloured motor vehicle, possibly a station wagon, with roof racks at Queenstown beach. He was wearing a wetsuit and using a yellow river kayak.
The witness believed she saw Mr Mudra coming around the point towards the beach as the other kayaker came ashore.
Police believed this man might be able to help with their inquiries.
"It's not suspicious. We believe they were the only two kayakers in the bay that afternoon. So we would like to ask this man 'did you see him?' to help us confirm the route Mr Mudra may have taken," Det Sgt Bartlett said.
Police had not excluded the possibility Mr Mudra walked off after beaching the kayak in the Lake Esplanade area.
He was wearing a beige-coloured long-sleeved woollen pullover, blue jeans, beige-coloured trainers and a light blue polo shirt and is described as about 185cm tall, weighing about 95kg with short grey hair. He is clean-shaven, wears wire-rimmed glasses and speaks English well but with a strong accent.
Mr Mudra had been living in New Zealand for the past two and a-half years.
