Amnesty International on Wednesday condemned countries in southern Africa for treating anti-government activists as "criminals" while hosting leaders accused of genocide such as Sudanese President Omar al-Bashir.

"Whilst activists in Angola, Swaziland and Zimbabwe were rounded up on the streets, Sudan's President Omar al-Bashir was permitted to travel unhindered to the AU (African Union) conference in South Africa," the rights agency said in its annual report.

Bashir is wanted by the International Criminal Court (ICC) for alleged war crimes related to the conflict in the Darfur region of Sudan.

South Africa, which is a member of the Hague-based ICC, did not arrest Bashir during the summit in Johannesburg last June on grounds that he had immunity.

But a court in the city ruled that the authorities were legally bound to arrest him.

"Something is clearly wrong when human rights defenders are treated like criminals, whilst those wanted by the ICC for genocide are treated like dignitaries," said Amnesty.

During their last AU summit in January in Addis Ababa, African leaders backed a Kenyan proposal urging a pullout from the ICC on the grounds that it unfairly targeted the continent.

But Amnesty's research director for Africa, Netsanet Belay, said that the "threats of withdrawing will only undermine justice for victims."

"African countries were founding fathers of (the) ICC. South Africa can't afford to betray those victims," said Belay.

Amnesty International also deplored rights violations in many of the southern African countries, notably Zimbabwe and Angola.

"In Zimbabwe, freedom of expression, association and peaceful assembly continued to be severely restricted," said Muleya Mwananyanda, the deputy director of Amnesty International in southern Africa.

In Angola, Amnesty said the government of President Jose Eduardo dos Santos was using defamation laws and state security legislation to "harass, intimidate, arrest and detain those peacefully expressing their views".