A search has resumed for a man who was swept downstream while hiking near Craigieburn Forest Park in Selwyn.

Police were alerted after the man fell during a river crossing on the Cass-Lagoon Saddle Track shortly after midday on Thursday.

“While attempting a river crossing, the man has fallen and been swept downstream,” Christchurch Police Search and Rescue Detective Cam Ellis said.

The man had been hiking with a friend, who was able to make his way back to State Highway 73.

A concerned motorist stopped to help and contacted Police.

The friend suffered minor injuries and was taken to Christchurch Hospital.

Police search teams, dog units, Land Search and Rescue volunteers, rescue helicopters from Garden City Helicopters and Main Divide Helicopters, and North Canterbury Coastguard searched the river and surrounding areas on Thursday.

The operation continued into the night, but the missing man was not located.

Search teams returned to the area on Friday morning, despite difficult and dangerous conditions.

“I want to commend the hard work of all those involved in the search,” Ellis said.

“Conditions are hazardous, and Land Search and Rescue volunteers, along with Police search teams, are currently working through snow, flooded rivers and an alpine environment to search for the missing man.”