Swaziland's largest music festival has sparked a war of words between organisers and opponents of King Mswati III's regime amid calls for a cultural boycott against the last absolute monarchy in Africa.

The Bushfire Festival, an annual music and arts showcase set for May 27-29, typically draws thousands of music lovers from around southern Africa to the tiny kingdom.

But dissidents are calling for a boycott this year in the hope of isolating Mswati, who is facing mounting pressure for reform amid a budget crisis that last month sparked anti-government protests which were violently put down by security forces.

"We have nothing against Bushfire but people must understand that South Africa is where it is today because of cultural boycotts," Lucky Lukhele, spokesman for the Swaziland Solidarity Network, a dissident group based in South Africa, told AFP on Tuesday.

Neighbouring South Africa was the target of international cultural and sporting boycotts during apartheid, and some activists say the isolation of the white-minority regime helped hasten the first democratic elections in 1994.

But festival organisers say it is a charity event that supports the same goals as those calling for a boycott.

"These guys have no idea what they are doing. If there is one progressive platform in Swaziland it is this one. We are about development and social responsibility," organiser Jiggs Thorne told AFP, saying 100 percent of the profits would go to a youth charity.

The festival was expected to feature international acts, including the Yale Concert Band from the United States, D'bi Young from Canada, Habib Koite from Mali and Goldfish from South Africa.

Mswati, whose fortune is estimated at $100 million by Forbes magazine, has ruled tiny Swaziland for 18 years.

The jet-set lifestyle of the 43-year-old king and his 13 wives has become increasingly controversial in the tiny kingdom, where nearly 70 percent of people live on less than a dollar a day.

Discontent over government moves to slash civil servants' salaries in the face of a crippling budget crisis erupted into street protests on April 13. The demonstrations were met with a brutal clampdown during which police beat and detained opponents.