JOHANNESBURG (Reuters) - U.S. pop star Madonna's attempts to adopt a Malawian child hit a snag after the court-appointed official on the case was refused permission to travel to Britain.

One of Malawi's leading weeklies reported on Sunday that the Minister of Women and Child Development Kate Kainja refused to allow Penstone Kilembe to travel to asses the suitability of Madonna and her husband, film director Guy Ritchie.

The minister was not immediately available for comment, but Kilembe confirmed the minister had stopped him making the trip.

Madonna took David Banda last October when he was 13 months old after his father Yohane Banda had placed him in an orphanage following the death of his wife.

The High Court of Malawi appointed Kilembe to travel to Britain twice and was to have relied on his testimony in ruling whether Madonna should adopt the child in a hearing next year.

The Malawi News newspaper reported that the minister accused Kilembe of obtaining an air ticket and money from Madonna without government approval.

"We have already contacted Madonna that someone else and not Kilembe will come to asses her, because we feel Mr Kilembe personalised the whole issue when other people can go," the Minister told the newspaper.

Kilembe dismissed suggestions that he personally asked Madonna for an air ticket.

"What this means is that the whole adoption process may crumble and David sent back to his village," he told Reuters.

Justin Dzonzi, a human rights lawyer who led a 65-member rights group challenge to Madonna's adoption, also said the minister's decision could halt the adoption process.

"The Minister cannot change what the court set by having another person to do the assessment, the court will not listen to anyone else apart from the one it appointed," he said.

Dzonzi filed the case arguing that Malawi laws forbid international adoption and therefore the government broke its own laws by granting Madonna an interim adoption.