Anti-government protesters torched a police station in Malawi's capital on Monday, raising tension in the destitute country that was last year rocked by the police killing of 20 people in similar protests.

The latest outbreak of violence followed the weekend arrest of the chairman of the government's Human Rights Commission. The commission had sharply criticised the administration of President Bingu wa Mutharika for the July 2011 crackdown, accusing his government of using unjustifiable violence and arrests to intimidate its critics.

Police spokesman Davie Chingwalu said the anti-government protesters had become violent after a demonstration they were holding was broken up.

"(They) set on fire a police station, a police vehicle and a house belonging to one of our officers after we stopped a rally, which could have potentially sparked more violence because of rising political tensions," he said.

Activists last week gave the president a 60 day deadline to account for his wealth, address the chronic fuel and dollar shortages that have added to the misery of the poor, and to restore diplomatic ties with former colonial master and major aid donor Britain. Similar demands led to the July protests.

Aid-dependent Malawi is searching for a lifeline after major donors cut funds over concerns about suspected human rights abuses and creeping autocracy.

The government is trying to persuade an International Monetary Fund delegation that arrived at the weekend to restart the funding, but Mutharika has no plans to meet the envoys.

Malawi's $79 million three-year loan programme with the IMF is on hold due to disagreements over Mutharika's handling of the economy.

There is a $121 million hole in the current budget, in part due to the suspension of the IMF loan programme. Britain and the United States have suspended aid packages worth hundreds of millions of dollars, putting pressure on a budget that relies on aid for about 40 percent of its funding.

Mutharika, a former World Bank economist who was first elected in 2004, said if foreign aid donors were not happy, they should simply pack their bags.

In recent days, the police have stepped up their presence in major cities.

The economy has seen GDP growth averaging 7.4 percent in recent years thanks to bumper maize harvests after farm subsidies were introduced, something that started in 2005. But life has become increasingly difficult in the past year due to shortages of fuel, medicine and foreign currency.