The former Wallaby and three of his family members were attacked at their Coorparoo home in Brisbane at about 3:00am on Monday.
Police said the attack was carried out with an axe, a knife and a machete.
Mr Kefu suffered serious injuries and was hospitalised with wounds to his abdomen.
His wife, son and daughter also sustained injuries and underwent surgery.
The alleged offenders – three boys aged 15 and one boy aged 13 – have been arrested and charged with 11 offences each.