In the last few days, the organisation has flown aid agency representatives and several country ambassadors into the Dadaab refugee camp in northern Kenya to assess the scale of the need.
The addition of the South African plane brings the number of MAF aircraft in Kenya to seven.
John Woodberry, MAF manager of disaster response and security said: "MAF is in contact with a number of relief organisations working in the area.
"We are ramping up our capacity to respond, should the need for relief flights continue to grow."
On Wednesday, the UN officially declared a famine in parts of southern Somalia. It is estimated that more than 10 million people across the Horn of Africa are in need of food aid.
Writing in the Independent, Christian Aid's head of emergencies Nick Guttmann said that the Dadaab Camp was "extremely overcrowded", with around 500,000 refugees packing a space intended for 90,000 people.
He warned that although the situation was serious in Somalia, northern Kenya was also being badly affected by the lack of rain.
Militias are adding to the problems in Somalia, he said, with some being assaulted or having their possessions stolen, and aid agencies being prevented from working in the country.
"The people arriving here are in a bad way," he said.
"They've lost everything and there are lots of cases of malnutrition. Many have travelled hundreds of kilometres to get here."