Western Australian Aboriginal activist and Nyoongah elder Clarrie Isaacs has died.

Mr Isaacs was in his mid-50s when he died in his home, near Dunsborough in the state's south, last night.

He was well known for his commitment to Aboriginal rights, in particular his campaign to make the area around the Swan Brewery a sacred site.

Fellow campaigner and Nyoongah elder Robert Bropho says the Aboriginal community is in mourning and that Mr Isaacs will be sorely missed.

"It's a big loss to the Aboriginal people and its cause and there's no substitute for Clarrie Isaacs," he said.

"We could trust in Clarrie because we know he could stand up and have an opinion against anything that's been said and inflicted upon Aboriginal people as a whole."