Naya Rivera feared dead: 911 call reporting Glee star missing released

Naya Rivera is missing presumed dead. Photo / AP

Police have released the 911 call that first reported Glee star Naya Rivera missing.

A woman told the 911 operator that her husband was one of the people who discovered the boat on Lake Piru that Rivera had hired with her 4-year-old son, Josey.

The woman mistakenly referred to the child as a girl in the call.

"The emergency is we have a missing person, we found a little girl in one of the boats by themself and the mum's nowhere to be found," the woman told the 911 operator.

"My husband was one of the people that was there."

The woman didn't have too many extra details, telling the 911 operator: "I'm going to find out more information, he just wanted to call it in."

A US Coast Guard helicopter flies over Lake Piru where actress Naya Rivera was reported missing. Photo / AP

The boat was discovered by employees from the boat rental company. They went looking for the boat 30 minutes after Rivera had failed to return it.

Josey was found on board wearing a life jacket and reportedly told authorities he and his mum went swimming earlier in the day but that Rivera failed to return to the boat.

Authorities are still searching the lake in southern California and have described it as a "recovery operation", meaning the actress is presumed dead.

Two helicopters, six boats and 25 divers are involved in the search.

Ventura County Sheriff's Department Captain Eric Buschow told the LA Times Josey was "in good health" following the ordeal.

"The family is going through a very traumatic time right now," Buschow said, later telling NBC LA: "This is considered to be a horrible accident."

The lake is up to 15m deep in some parts and visibility is poor.