Update: The search for a fisherman who remains in the water after being washed off rocks at Steep Point has been suspended until tomorrow.
Four fishermen have been pulled from the water and rescue crews today were trying to recover one person who has yet to be found.
Police said the rescue would continue at first light tomorrow.
It is believed eight people were hit by a big wave at the fishing spot near Shark Bay, but three managed to scramble to safety.
Four men were taken to Denham for medical attention this evening aboard volunteer marine rescue vessel Tamala Rose.
They arrived at Denham at 6pm and are believed to have suffered only abrasions and mild hyperthermia.
All four men are conscious and were able to speak with their rescuers.
It was originally thought that a fifth person who is missing was sighted near cliffs. Police now say it is unclear whether the object sighted was a person or body.
Rescue crews found it difficult to get to where the object was spotted.
Aircraft this afternoon were searching an area of 6 nautical miles along the coast for the remaining missing person.
Police, Denham volunteer rescue craft and the State Emergency Services all responded to the incident.
It is understood the SES received a call at 11.19am.
A local plane joined the search and the police helicopter were sent to the scene from Geraldton.
Three boats from Denham rushed to the scene.
Earlier a police spokeswoman said that four of the people were seen swimming 300 to 400m offshore.
The spokeswoman said four men could be seen waving as the aircraft flew over them.
She said the people, who were part of a larger group, were fishing off rocks when they were swept off by the wave.
It is understood the group includes a father and a son, an uncle and two unrelated friends.
The ages of the group members ranged from 16 to 47 and they are all believed to be “strong and capable”.
It is not yet known which member of the group is still in the water.
The Royal Flying Doctor Service says an aircraft sent to Shark Bay would remain on standby until the five people were pulled from the water.
They say the group fell 10 metres from a cliff into the water below.
Weather conditions in the area are said to be windy and overcast with some rain.
The spokeswoman said the weather conditions were “not favourable”.
There are choppy conditions in the area, with 2 to 2.5m swells and 35km/h winds with squalls.
Steep Point, about 700km north of Perth, is managed by the Department of Environment and Conservation and is favoured by anglers.
The Steep Point website says the area is part of the Shark Bay World Heritage area and is widely regarded as one of the finest landbased game fishing locations in the world.
The area includes the Zuytdorp Cliffs, which has 60 meter drops in some parts.
A permit is required to enter Steep Point, which is only accessible by four-wheel-drive.
It is the most westerly point of mainland Australia and is a popular game fishing location with a rock fishing platform.