Uniformed police and officers in waterproofs scoured the water of dam and surrounding area yesterday morning after the items of clothing were found on the bench.
A police helicopter was also seen overhead as other officers stood by, and investigations were carried out into where the clothes had come from and who they belonged to.
Sections of Murdieston Street near to the scene were taped off while officers waded through the water and searched surrounding areas.
The find prompted fears of a missing person but police officers carried out a full search and found nothing untoward.
A spokesman for Greenock police said: "Because clothing had been found we searched the area comprehensively and the helicopter was brought in to make sure nobody was in the area.
"The marine unit also carried out enquiries to ensure nobody was in the water. Thankfully both searches came proved negative.
"The clothing could have came from anywhere but there have been no reports of missing or vulnerable people. The incident has now been closed."