Women in Malawi will stage a sit-in to defend their right to wear pants after police arrested a gang for terrorising trouser-wearing women by stripping off their clothes, an organiser said Thursday.

"We are calling on all women and men of goodwill to urgently converge on Friday for constructive engagement on the protection of women and the defence of their rights in a democratic Malawi," Seodi White, a lawyer and leading women's rights activist, said in a statement.

White said protesters would gather in the commercial capital Blantyre "in solidarity with the victims and to express our indignation at such barbaric treatment of mothers, wives and daughters of our country."

Police said Wednesday they had arrested 15 "thugs" in the capital Lilongwe, 350 kilometres (220 miles) north of Blantyre, for terrorising women by stripping them of their trousers or shorts and robbing them.

Until 1994, women in the deeply conservative southern African country were banned from wearing pants under the dictatorship of Kamuzu Banda.

Vice President Joyce Banda, who has fallen from favour with President Bingu wa Mutharika amid a split in the ruling Democratic Progressive Party, told journalists Wednesday the incident was the result of economic woes in a country that is currently racked by shortages of fuel and foreign currency.

"There is so much suffering that people have decided to vent their frustrations on each other," she said.