Police have reached a body in the Blue Mountains and confirmed it matches the description of missing Sydney man Gary Tweddle.

The man's body was spotted by an ambulance rescue helicopter in a tree growing out of a crevice in a cliff at Leura on Monday afternoon.

"My best friend has been taken from me and it's so hard": Gary Tweddle with his girlfriend, Anika Haigh.

A police officer at the scene said a striped shirt found near the body matched the description of the one Mr Tweddle was wearing on the night he went missing.

It is seven weeks to the day since the 23-year-old, from Cremorne on Sydney's north shore, vanished from the Fairmont Resort at Leura.