It has been reported that a 19-year-old woman was seriously sexually assaulted at around 3am on Sunday, September 5, while walking between Cladach Beach and the Co-op, known locally as 'the wee Co' or I Fisherman’s Walk.
The woman was wearing dark clothing and had found herself separated from her friends when the incident happened.
Detectives are now appealing for any witnesses to contact them who may have seen the woman or anyone acting suspiciously around 3am in that area.
Detective Inspector Stephen McCulloch, based in Saltcoats, said: "I would ask anyone who saw a 19-year-old woman in the Fisherman's Walk area, possibly walking with another person, to contact us.
"We're trying to establish the full circumstances so any information related to this might prove to be crucial."
If you have information you should contact 101 quoting incident number 1713 of September 5.