Pretoria - President Jacob Zuma has conveyed condolences to the families of the victims whose lives were lost when a Yemen airbus crashed in the Comoros archipelago in the Indian Ocean on Tuesday.
At least 150 passengers are thought to have been on board Airbus 310, flight 626.
The South African Department of International Relations and Cooperation is in constant contact with the French and Comoran authorities to establish whether there may have been South African nationals on board.
"South African families who may have had relatives on board the ill - fated plane are advised to contact the department for possible consular assistance," the department said.
An employee working at Yemen's airport control tower said on condition of anonymity that an Airbus A310 belonging to Yemenia Air crashed with 150 people on board some 15 minutes before its landing in Moroni, the capital of Comoros.
"Yes, there is a crash, but now there is not much information about when and where it occurred," he said.
According to the airline's schedule on its website, Flight 626 flew to Moroni from Sana'a at 8pm local time, Monday. The plane was scheduled to land at the islands on 11:59pm local time.
Comoros Vice President Idi Nadhoim from the airport said the plane crashed in the early hours of Tuesday, but no immediate news was available on whether there were any survivors.
French military planes have already taken off from the Indian Ocean islands of Mayotte and Reunion to search for possible survivors.
Media reports cited Yemenia airport official as saying that most of the passengers on the plane were believed to be Comoros residents returning from Paris. Passengers also include French citizens.
Meanwhile, media reports vary about the number of people aboard the plane, with some saying 150 while others putting it at somewhere between 142 to 150.
The Comoros is an archipelago of three main islands situated about 1 800 miles (2 900 kilometer) south of Yemen, between Africa's southeastern coast and Madagascar.