The rubbish consisted of old printers, their boxes and other household waste and was placed next to a bin at the Rockingham Regional Memorial Park in Baldivis.
Joan Russell said she visited her son’s grave every Monday.
“I have seen rubbish (there) before but this is the most I have seen,” she said.
“It is only a couple of metres from his plot – it’s like throwing rubbish on it.
“To disrespect his loved ones like that it is wrong.”
Mrs Russell said she wanted people to consider the impact of their actions on others.