BLANTYRE, Malawi, April 11 – Malawi has launched a stinging attack on US pop icon Madonna, accusing her of expecting "gratitude" and VIP treatment during a visit last week to her charity work in the southern African country.

It was "strange and depressing" that the singer seemed to want "Malawi to be forever chained to the obligation of gratitude" for having adopted two Malawian children, said President Joyce Banda's government on Wednesday.

"Kindness, as far as its ordinary meaning is concerned, is free and anonymous," it added in a four-page statement.

"If it can't be free and silent, it is not kindness; it is something else. Blackmail is the closest it becomes."

For the first time, the 54-year-old superstar was denied use of the VIP section at the airport on the trip and had to use the ordinary passenger section.

She was visiting schools her charity has built in central Malawi with her four children, including Malawian-born David Banda and Mercy James.

Madonna's fame did not mean she had to be given "state treatment", and she was "like any other visitor" not on an official invitation, said the highly critical statement.

A dig was also made about Madonna's charity work, with the government saying she urgently needed to learn "the decency of telling the truth".

"For her to tell the whole world that she is building schools in Malawi when she has actually only contributed to the construction of classrooms is not compatible with manners of someone who thinks she deserves to be revered with state grandeur," it said.

"The difference between a school and a classroom should be the most obvious thing for a person demanding state courtesy to decipher."

Madonna two years ago abandoned a $15 million girls' academy, saying she would instead build community schools to accommodate more students.

The project for the school, which was to be headed by Banda's sister Anjimile Oponyo, was mired in allegations of mismanagement and with $3.8 million of unaccounted funds spent.

The government on Wednesday dismissed allegations of Oponyo's involvement in the matter.

But Madonna's side said Oponyo, who is suing her charity after losing her job, had a grudge and had used her appointment as education secretary to pursue.

"Madonna is the largest individual philanthropist in Malawi and we are a bit surprised that the President is using her office to pursue her sister's financial interests," said the star's philanthropy manager Trevor Neilson.

"We will continue to fund programmes that support children in Malawi, a country where millions of children suffer every day," he added.

The new schools, which had been trashed as classrooms, were built as per models in the country and around the world, said Neilson.

"In many of these communities students were previously learning under trees," he said.

The divorced singer also faced controversy over her adoptions in 2006 and 2009 from Malawi orphanages, with rights groups claiming she received special treatment from officials.

Madonna's charity has poured millions of dollars into the support of orphans in Malawi, which is ranked by the UN Human Development Index as one of the world's 20 least developed countries.

The government, which relies heavily on aid, said it was open to philanthropists but they should "not hold to ransom the president and any official... because they showed some kindness to any Malawian".