Madonna visited a Malawi rehabilitation centre for children and prostitutes yesterday amid calls by local media for greater transparency in the pop star's activities in the country.

A day after teenagers threw stones at journalists trying to cover the US pop diva's visit to a local orphanage, she was greeted by people waving welcoming signs before being whisked into the centre while reporters were kept outside.

Welcome Madonna, Adopt More Poor Orphans, one sign said, referring to the star's adoption of a young Malawian boy.

The influential Daily Times newspaper said it backed Madonna's pledge to help Malawi, but urged the star and her handlers to be more open after the furore surrounding her last trip when she started the adoption process.

"It is surprising that just like her first trip, Madonna's second trip to Malawi is also shrouded in secrecy," the Daily Times said in an editorial.

"This kind of behaviour is what gives room to speculation and in the end, people are fed with wrong information which may lead to wrong conclusions and actions."

Madonna's spokesman has flatly denied media reports the star was considering adopting a second Malawian child, saying her current trip was aimed at promoting her charitable work. But the controversy has continued amid a lack of official information about her activities.

Schoolchildren pelted reporters' cars with stones on Tuesday to keep them away from the orphanage where she brought one-year old David Banda - the boy she is adopting - to meet his biological father.

The director of the orphanage on Monday vowed security during the visit would be tight and said Madonna's camp had requested the media be kept out.

Madonna eventually invited journalists into the orphanage where she answered a few questions and posed for photographs with Banda and her daughter Lourdes.

The visit comes some six months after Madonna and her husband Guy Ritchie signed interim adoption papers for Banda, who will stay with the couple for 18 months before a decision by the Malawian government on whether to finalise the adoption.

The decision to take Banda back to Britain sparked criticism from some rights groups that Madonna was using her fame and wealth to circumvent adoption laws in the country. The singer denied the charges.

Madonna is paying for a new clinic to be built in the Malawian village of Gumulira and is supporting efforts by aid groups to help improve food security and education there.

The Social and Rehabilitation Centre, a small white building in a Lilongwe township, is another beneficiary of Madonna's Raising Malawi charity.