The incident happened at around 12.40pm on April 2.
A man aged in his 60s was fishing at the edge of the promenade near the Orford Road end of Sea Road when he was assaulted by a man who was walking his dog.
The suspect is then alleged to have accused the other man of casting the line from his fishing rod too near to his dog.
He then pushed the victim from his chair, causing him to fall 3ft onto the beach.
It is understood that the victim sustained no injuries as a result of the fall.
The male suspect is described as being in his 70s, approximately 5ft 11in tall and of a stocky build.
He was wearing a brown coat, a dark woolly hat and was walking with a black and white border collie breed dog.
Anyone who witnessed the incident or has any knowledge of it should contact Suffolk police on 101, quoting crime reference number 37/17757/18.
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