Searchers scouring the Canterbury coast for three missing fishermen have found a life raft and an emergency locator beacon.

But there's still no sign of the men or their FV Jubilee fishing boat.

Georgia Nelson reports,

"Two coastguard boats, three commercial vessels, a rescue helicopter and a plane are searching an area 20 kilometres from the Rakaia river mouth. The police dive squad are on their way. A distress call was made from the boat at 4:30 this morning and senior constable Paul Beaver says conditions are severe with high seas and strong winds."

The distress call from the fishermen was received at 4.30 this morning off the Rakaia River mouth.

Harsh weather has delayed rescue services trying to reach the search area, 20km off the river mouth.

Police say the search is now a recovery operation.

Inspector Craig McKay says they've searched extensively since 6.30 with no sign of the men.

"There's always hope, but it's been several hours now and the information we have from the experts who we reached out to has indicated that the phase we need to move into is one of recovery."

The public are being warned to steer clear of the area.