A UN human rights watchdog has called on Saudi Arabia to end "severe" discrimination against girls and to repeal laws that allow the stoning, amputation, flogging and execution of children.

The Committee on the Rights of the Child also condemned the Saudi-led coalition's air strikes in Yemen, which it said had killed and maimed hundreds of children, and its "use of starvation" as a tactic in that war against Iran-backed Houthis.

The committee's 18 independent experts examined the kingdom's record of compliance with a UN treaty protecting the rights of people under the age of 18.

Bandar Bin Mohammed Al-Aiban, chairman of the Saudi Human Rights Commission, who led a Saudi delegation to the committee's review, told the body that sharia, Islamic law, was above all laws and treaties, including the Convention on the Rights of the Child. But the kingdom had the political will to protect children's rights, he said.

However, the UN experts voiced deep concern that Riyadh "still does not recognise girls as full subjects of rights and continues to severely discriminate [against] them in law and practice and to impose on them a system of male guardianship".

Traditional, religious or cultural attitudes should not be used to justify violations of their right to equality, they said.

Children of Shi'ite Muslim families and other religious minorities are persistently discriminated against in their access to schools and justice in the Sunni-ruled kingdom, they said.

Children over 15 years are tried as adults and can be executed, "after trials falling short of guarantees of due process and a fair trial", the report said.

A mass execution of 47 people took place on January 2 this year in which at least four of the victims were under 18 when they were sentenced.

Referring to Islamic provisions for a relative to exact retribution for murder and to breaches of the strict Islamic behavioural code, Saudi Arabia had previously said in its submission to the UN: "Children who have reached the age of 15 and commit a 'qisas' or 'hudud' offence face 'qisas' or 'hudud' penalties depending upon their offence although the penalty is not enforced until they reach the age of 18."

Hudud penalties include execution, amputations, flogging and stoning to death.

The UN experts urged Saudi authorities to "repeal all provisions contained in legislation which authorise the stoning, amputation and flogging of children".

Saudi Arabia should "unambiguously prohibit the use of solitary confinement, life sentences on children and child attendance of public execution" their report said.

All forms of sexual abuse against children should be a crime and perpetrators prosecuted, the experts said.

They cited the case of Muslim preacher Fayhan al-Ghamdi, saying his charges were reduced and he was released from jail "after having raped, tortured and killed his five-year-old daughter" in 2012. His daughter Lama died having spent 10 months in hospital after doctors were unable to treat her injuries. After a public outcry al-Ghamdi was later jailed for eight years and sentenced to 600 lashes.

Additional reporting by Reuters.