It would be a serious breach of international law if it was proved that he had been forced to quit, said the country's Foreign Minister Nkosazana Dlamini-Zuma.
"The suggestion that President Aristide may have been forced out of office, if true, will have serious consequences and ramifications for the respect of the rule of law and democracy the world over," she said.
"The international community must not be seen to be wavering in its commitment to democracy and the respect for the rule of law, particularly in the face of anti-democratic forces," Dlamini-Zuma said.
"In this regard, we join in the call for an investigation under the auspices of the UN to clarify these circumstances leading to the departure of President Aristide," she said.
Dlamini-Zuma, who is currently in New Delhi, also slammed the United Nations for its slow-footed action on Haiti.
"The slow response of the UN Security Council to pleas for assistance by the government of Haiti, however, remains a matter of serious concern," she said.
She said the Security Council "should remain true to its mandate of being an organ for the collective security for all and therefore respond speedily to conflict situations with a view to the restoration of peace and stability."
"The slow response of the UN Security Council to pleas for assistance by the government of Haiti, however, remains a matter of serious concern"
foreign minister, South Africa
On Wednesday, Caribbean Community president Percival Patterson described Aristide's departure from power as a "dangerous precedent," and said that area leaders will not negotiate with rebel leaders in Haiti.
The Caricom chief also called for a top level independent investigation into Aristide's departure.
"The unconstitutional removal of any leader cannot be condoned," Patterson said.
"What has happened represents a very dangerous precedent not only for Haiti but for all democratically elected leaders and governments throughout the world," he said.
Aristide, speaking from exile in the Central African Republic, claims he was pushed from power by the United States. Washington has strenuously denied it did other than accompany Aristide to safety and exile once he called for help.