Kosit Nilrat said he had assigned 17 officials to clean up the beach at Ao Bor of Koh Rung every morning for more than a week.
The garbage, which landed along a 300-metre stretch of beach, mostly comprised plastic bags, plastic bottles and plastic bins dumped by humans into the sea.
Kosit said the amount of garbage showed that a lot of tourists and people living on the coast had dumped garbage into the sea. Some of the bottles had words in foreign languages, indicating that they had floated in from neighbouring countries, he added.