SA man admits killing partner and her kids

An Adelaide man will face sentencing submissions in Adelaide on Friday over the brutal murder of his partner and her two children.

Steven Graham Peet strangled Yvette Wilson-Rigney and her children, Amber, aged six, and five-year-old Korey, with cable ties before trying to conceal their bodies at a property north of Adelaide in May 2016.

He admitted killing Ms Wilson-Rigney at the start of his Supreme Court trial last year and on Monday also admitted murdering the children.

The 31-year-old faces a head sentence of life in jail with a non-parole period to be set after sentencing submissions including victim impact statements.

The bodies of Ms Wilson-Rigney and the children were all found with cable ties around their necks and hidden under clothes and bedding and, in the case of the boy, under a child's play tent.

The young girl had adhesive tape wrapped around her head and a sock had been stuffed in her mouth.

The young boy had parts of his body wrapped in tape and his hands and feet were secured behind his back in a hog-tied fashion.

Peet initially pleaded not guilty to the murder of the children, claiming he was in a "dissociative state" at the time of the killings, but abandoned his claims on Monday.