The search for a Roxburgh man believed to be missing in the Clutha River will continue toward the end of the week when river levels are likely to be lower.

Existing levels were making the hunt for 28-year-old Paul Wilson difficult, said Detective Sergeant Derek Shaw, who is leading the effort.

Search and rescue staff and private volunteers continued exploring the Clutha River and shoreline over the weekend without success.

"The best conditions for searching are when the river is at a lower level," Mr Shaw said.

"Given the large amount of rain that has fallen, the river is running high.

Contact Energy is working with Police to consider the possibility of lowering the river to minimum levels towards the end of the week," he said.

Mr Wilson went missing last Wednesday around midday at the Talla Burn stream near Beaumont where he was taking water samples.

Mr Shaw said the volume of water flowing through the river toward the end of the week would determine the direction and approach the search would take.