Madagascar's authorities wanted a plane carrying former leader Marc Ravalomanana to land away from the capital so he could be arrested without trouble from with his supporters, officials said.
Ravalomanana's plane was turned back from the capital Antananarivo because of the risk of "certain troubles from Marc Ravalomanana activists", said a statement released late on Saturday by Madagascar's transitional authorities.
Officials wanted the plane to land instead at Morondava in the west of the country, where police would have arrested him.
They had previously warned the airline that they would be arresting Ravalomanana if he was on board, the statement added.
The flight would then have been allowed to continue on to Antananarivo.
But the captain of the South African Airways-operated flight carrying Ravalomanana and other passengers decided instead to turn back to Johannesburg.
Ravalomanana was trying to return to Madagascar after a three-year exile.
Officials closed the airport near Antananarivo after thousands of his supporters flocked there to greet him.
Ravalomanana was driven from power after his presidential guard killed protesters in February 2009.
A transitional government was formed in November, in a deal that allowed the return of political exiles. Another deposed leader, Didier Ratsiraka, recently returned from exile in France without incident.
But Ravalomanana had been previously warned he would be arrested if he returned to the island nation.
He has been sentenced in absentia to life in prison and hard labour for the deaths of the protesters.
Following Ravalomanana's thwarted attempt to return, his party walked out of the fledgling unity government. - ANP/AFP