The 10-month son of South African rugby star Jannie du Plessis has died in an accidental drowning at the family home near Johannesburg.

Jan Nathaniël's death occurred while the du Plessis family was celebrating the former Springbok prop's 39th birthday at their house in Krugersdorp.

"On November 16 at about 7 p.m., police were called to a scene of drowning whereby a 10-month-old baby boy fell in the swimming pool," a police statement said, according to The Times of London.

Jannie du Plessis played 70 tests for South Africa and was part of the 2007 side that won the Rugby World Cup.