South Africa's main opposition party called Sunday for an investigation into reports that Pretoria helped supply arms to Madagascar's former president as he tried to quash protests against his rule.

The Democratic Alliance (DA) said ex-president Marc Ravalomanana may have illegally used South Africa as a transit point to import Chinese-supplied riot gear in the run-up to his 2009 ouster and that South African arms regulators may have illegally authorised a deal for similar equipment.

"The National Conventional Arms Control Committee should immediately authorise an investigation into reports that (Ravalomanana) used South Africa as a transit point to import Chinese-supplied riot control gear prior to the 2009 coup," DA lawmaker David Maynier said in a statement.

Maynier said the committee had also authorised a rush sale of 2.3 million rand ($300,000, 230,000 euros) of riot control equipment to Madagascar in 2009.

"The riot control gear appears to have been exported to military or paramilitary forces just prior to the coup in Madagascar," he said.

"There was therefore a high probability that the riot control gear would be used for internal repression."

The DA's call comes after WikiLeaks published a 2009 US diplomatic cable that said Ravalomanana had used South Africa as a transit point for Chinese shields, body armour, tear gas, rubber bullets and uniforms after going on a "buying spree" for crowd control equipment.

The cable raised concern that the equipment could be deadly in the hands of under-trained Madagascan security forces.

Ravalomanana has been living in exile in South Africa since shortly after his ouster by the then-mayor of the capital, Andry Rajoelina.

Ravalomanana was sentenced in absentia to life in prison and hard labour for the death of some 30 opposition protesters killed by his presidential guard in February 2009 when they opened fire without warning on a crowd outside the presidential palace.

He has been trying to go home to participate in new elections under a roadmap brokered by regional mediators, but has repeatedly been foiled by Madagascan aviation officials refusing to allow his return.