Grief-stricken friends have paid tribute to three members of a family with Australian ties who were murdered in their South African home.

Martin van Breda, 55, his wife Theresa, 54, and son Rudi, 22, were found dead at an exclusive golf resort in Stellenbosch, about 50km east of Cape Town, on Tuesday, media reports say.

Daughter Marli, 16, is in a critical condition, while another son, Henri, 20, has minor injuries.

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South African media reported the victims were killed with an axe, but authorities have not disclosed any details.

The family lived in parts of Australia for several years before returning to South Africa last year.

The Department of Foreign Affairs and Trade says it is providing consular assistance.

Mr van Breda was a businessman who recently worked in Queensland for Engel and Volkers Australia, according to his Linked In profile. The company sells and rents premium residential property, commercial real estate and yachts.

Rudi and Henri both attended Scotch College private school in Perth.

Headmaster Alec O’Connell said in a statement that Rudi and Henri were students at Brisbane House and the family was a valued part of the school community.

“The Scotch community sends our thoughts and prayers to the van Breda family during what is a significant family tragedy,” he said.

“At this time, our role is to provide support for the family and those who studied with the boys or knew the family.”

According to his Facebook profile, Rudi was studying a bachelor of science at the University of Melbourne.

Afif Norzal posted on Rudi’s profile: “You are a true blue genuine mate my friend. At times when I didn’t have anyone to talk to, you would definitely make me feel the most welcome and always cracking me up regardless. I am going to miss you.”

Shota Konno wrote: “It was an honor knowing you and I am proud to say that I had (a) good time at Scotch with you. Miss you buddy, rest in peace.”