The UN human rights chief on Thursday urged the Saudi king to pardon a blogger sentenced to 10 years jail plus 1,000 lashes, and to review the "cruel" penalty of flogging.
"Flogging is, in my view, at the very least, a form of cruel and inhuman punishment," UN commissioner Zeid Ra'ad Al Hussein said in a statement.
"Such punishment is prohibited under international human rights law," he added, appealing to King Abdullah "to halt the public flogging by pardoning Mr (Raef) Badawi, and to urgently review this type of extraordinarily harsh penalty".
Badawi received a first instalment of 50 lashes last Friday and is expected to have 20 weekly whipping sessions until his punishment is complete.
The co-founder of the now-banned Saudi Liberal Network, he has been found guilty in a Saudi court of insulting Islam.
His wife Ensaf Haidar, who sought asylum in Canada with her three children after Badawi was jailed in June 2012, has called for his release.
The United States, Amnesty International and Reporters Without Borders (RSF) have denounced the flogging as a horrific form of punishment, saying Badawi was exercising his right to freedom of expression.
Ottawa has also condemned the punishment and called for a pardon.