UPDATE: A 26-year-old quad bike rider who went missing in a forest in Western Australia has been found injured.

The man became separated from a group of friends he was with in Redmond Forest near Albany around 3pm yesterday.

When he failed to return, they alerted authorities.

Police advised at around 9.45am today that he had been found after an intensive search.

It was earlier feared that he had crashed his quad bike, but that has not been confirmed.

"He has some injuries and is being taken by ambulance to hospital," police said.

"At this time, the exact circumstances that led to him being injured are not known.

"Further inquiries are being made, however medical treatment is the first priority."