The incident occurred at some point between 2.30 pmto 3.30pm on Wednesday, 18 May.
Two women were walking along the Cliff Path footpath, which runs between Sizewell and Thorpeness, when they were approached by an unknown man walking in the same direction, who reportedly walked past them as though in a hurry. After a short while the man stopped and appeared to be urinating, before he walked away.
Soon after, the women saw the man again standing naked behind the sand dunes on the beach side of the footpath. He reportedly walked towards the beach, and then turned to walk towards the women.
There was no exchange in conversation and the women continued to walk along the footpath.
A few moments later the man reappeared behind them, fully clothed and followed them a short distance.
The man is described as white, approximately 5ft 9ins in height, aged in his 40s and of slim build. He had short, wavy dark, greying hair and was wearing a white top or T-shirt, black sports-style jacket and was carrying a small black rucksack. He may also have been wearing thin, wiry glasses.
Anyone who may have seen a man matching this description, or who may have information that may assist with the investigation is urged to contact Leiston Safer Neighbourhood Team, quoting crime reference 37/30773/22 by calling 101.
Alternatively contact the independent charity Crimestoppers anonymously on 0800 555 111, or via their online form: www.crimestoppers-uk.org