A man was seen to fall from the bridge into the Tay, nearer the Fife end of the bridge. He is described as white, in his 50s, wearing a dark tammy style hat, a large black winter coat over a dark green jumper or shirt, grey jeans, and black shoes.
He was also seen to be smoking a cigarette he had taken from a tobacco pouch.
The incident occurred at around 3:40pm yesterday.
A police spokesman said: “We have not had any persons reported missing to us who match this description at this time, and we need to identify who he is, along with trying to find him.
“It has been confirmed that he entered the bridge walkway fron the Dundee end.” If you have any information which could assist police, please call 101 or speak to any Police officer. Our reference is CR/76/18.