UN chief Ban Ki-moon has slammed as "unacceptable" the public flogging of a veiled woman in Pakistan's North West Frontier Province.

"This is just unacceptable," he on Tuesday told a press conference in answer to a question about the case. "Respecting and upholding basic human rights is universally accepted."

On Monday Pakistan's top judge ordered government officials to submit a detailed report within 15 days over the flogging case, an incident that incensed the volatile Asian nation.

Pakistani Chief Justice Iftikhar Mohammad Chaudhry gave the directive as eight judges opened a hearing into the case, apparently that of a 17-year-old girl who was caught on an amateur video being whipped face down on the ground.

The date of the flogging, the location and the details of the woman's alleged crime have been confused but the footage showed two men pinning her down while a bearded man in a turban flogged her 34 times with a whip.