The wife of ousted Madagascar president Marc Ravalomanana was on Saturday blocked from returning home on a commercial flight from exile in South Africa, an airline spokeswoman said.

The Ravalomananas fled to South Africa in 2009 after the then president was ousted with the military's backing by Andry Rajoelina, then mayor of the capital, Antananarivo.

Airlink, a regional carrier affiliated with South African Airways, said South Africa's foreign ministry had ordered it Saturday not to fly former first lady Lalao Ravalomanana back to Madagascar -- a story the foreign ministry's spokesman denied.

"We would have continued as normal and everything as normal but basically we were told by foreign affairs that she was not allowed to travel," Airlink spokeswoman Karin Murray told AFP.

"Our foreign affairs office gave us the notification, so it's a diplomatic matter."

But foreign ministry spokesman Clayson Monyela said his office, the Department of International Relations and Cooperation (DIRCO), was not involved and that the Ravalomananas' return to Madagascar was being handled by mediators from the 15-nation Southern African Development Community (SADC).

"It's not true. DIRCO couldn't take that decision. The mediation in Madagascar is a SADC initiative," he told AFP.

"We don't even know that she was supposed to be going back."

Ravalomanana's South African public relations firm declined to comment, and his spokesman and personal assistant did not immediately return phone calls.

Meanwhile in Antananarivo, where several thousand supporters had gathered to welcome the former first lady, top Ravalomanana ally Mamy Rakotoarivelo, speaker of the lower house of the country's transitional parliament, accused the Madagascan transport ministry of blocking her return.

"Today we learned that the transport ministry sent a letter to the director-general of Airlink saying that if the company agreed to let Mrs Ravalomanana on board it would be at its own risk and peril," Rakotoarivelo told AFP, accusing the ministry of intimidation.

"Her luggage had to be taken off the plane. She had her boarding card in her hand," Rakotoarivelo said.

Transport Minister Benjamina Ramanantsoa confirmed his ministry had sent a letter to Airlink but denied it was designed to intimidate.

"It wasn't exerting pressure, it was just to let everyone know one another's responsibilities," he told AFP.

"I can't force a private airline to board or remove anyone."

The aborted trip comes two weeks after the Ravalomananas boarded an Airlink flight home, only to be forced to do a U-turn in mid-air when Madagascan authorities closed the country's main airports.

Ravalomanana has been eager to return home despite a threat from Madagascan authorities to arrest him on arrival after he was sentenced in absentia to life in prison and hard labour for the killing of 30 protesters by his presidential guard in 2009 in the run-up to his ouster.

A road map signed in September by most of the Indian Ocean island's main political parties, designed to steer the country to new elections and restore constitutional rule, calls for Ravalomanana and other exiles to be allowed to return home unconditionally.