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Police have named a man missing at Lake Poerua, south of Lake Brunner near Greymouth, after a canoe he was in overturned in high winds spilling him into the water.

Sergeant Brett Simon said the missing man was Alan William Hill, 45, self-employed of Greymouth.

Mr Simon said emergency services were called to the lake around 11.20am after reports two men had overturned their Canadian canoe with only one making it back to shore.

A search was conducted for Mr Hill, who was last seen having difficulty staying afloat, but he was not found before nightfall and the search has been abandoned for the night.

Police divers and a rescue helicopter will return to the lake tomorrow to resume their search.

Earlier today Constable Sean Judd of West Coast Search and Rescue said hope of finding Mr Hill was "not looking too flash".

"There's just a few guys on site and they're doing what they can but they're not very far away from winding that up," Mr Judd said.

Canterbury West Coast Air Rescue helicopter pilot Nigel Clark said he flew over the lake but saw no sign of Mr Hill.

He said the lake was choppy and appeared black from the air because of weed and the tannins in the water.

Mr Clark said he was told Mr Hill was wearing camouflage clothing and went "straight down".

The man who made it to shore was a 47-year-old self-employed man from Nelson, who was treated by St John paramedics for shock and hypothermia.

He earlier made it to a nearby farm house where he raised the alarm.