Piles of human waste and dog treats filled with snail pellets have been found at a Mitcham park, which has prompted safety fears.

Signs have now been posted around Simpson Park as Heatherdale Creek Parklands Advisory Committee warn park-goers about the hazards.

Committee secretary Val Turnball told the Herald Sun that at least four piles of human waste had been dumped in the park over the last two months, with the most recent batch being found in the last week, less than a metre from the footpath.

They believe the large amount of faeces is being caused by someone emptying a poortaloo.