A Saudi man who raped his five-year-old daughter and tortured her to death has been sentenced to pay "blood money" to the mother after having served a short jail term, according to activists.

The man, said to be a religious scholar who is also a regular guest on Islamic television networks, confessed to having used cables and a cane to inflict the injuries, activists from the group Women to Drive said in a statement on Saturday.

Lamia was admitted to hospital on December 25, 2011, with multiple injuries, including a crushed skull, broken ribs and left arm, extensive bruising and burns, the activists said.

They said the father had doubted his daughter Lama's virginity and had her checked up by a medic.

She died last October.

Randa al-Kaleeb, a social worker from the hospital where Lama was admitted, said the girl's back was broken and that she had been raped "everywhere", according to the group.

The activists said that the judge had ruled the prosecution could only seek "blood money and the time the defendant had served in prison since Lama's death suffices as punishment".

Three Saudi activists, including Manal al-Sharif, who in 2011 challenged Saudi laws that prevent women from driving, have raised objections to the ruling.

The ruling is based on national laws that a father cannot be executed for murdering his children, nor can husbands be executed for murdering their wives, activists said.