Christina Fernandez, Argentina's president, and Jose Insulza, the head of the OAS, are set to accompany Zelaya during his planned return to Honduras on Thursday in a show of support, an Argentinian foreign ministry source said on Tuesday.
The adoption of the general assembly resolution came as supporters of both the sacked president and his interim replacement turned out in Tegucigalpa, the Honduran capital.
Al Jazeera's Lucia Newman, reporting from Tegucigalpa, said hundreds of people had gathered in support of Zelaya while in another part of town many thousands of people had gathered near congress to support the coup leaders.
"I think things are really gearing up for a confrontation. People here on the streets are trying to draw up instructions to Zelaya supporters to welcome Zelaya when he comes back - but the military has said that he will be arrested if he does this," she said.
Roberto Micheletti, whom congress appointed as Zelaya's replacement just hours after the coup, has said he will have the ousted president arrested if he returns to Honduras.
Micheletti, the former parliamentary speaker from the same Liberal party as Zelaya, vowed not to resign as interim president and said only an armed invasion would restore his ousted predecessor.
"No one can make me resign," he said.
"[Zelaya] can no longer return to the presidency of the republic unless a president from another Latin American country comes and imposes him using guns."
"I was appointed by congress, which represents the Honduran people. Nobody can make me resign unless I break the laws of the country," he told the Associated Press.
His interim government said it would send a delegation to Washington on Wednesday for talks on the crisis.
Micheletti has insisted that Zelaya was not ousted through a coup but through "a completely legal process as set out in our laws", calling the move an "act of democracy".
Zelaya was removed from power as he was about to press ahead with a non-binding referendum on constitutional change on Sunday that congress and the courts had declared illegal, accusing him of trying to change the charter so he could run for a second term in office.
Before the UN General Assembly's condemnation of the coup, the sacking of Zelaya was roundly criticised by Latin American countries and the United States.
Members of the Bolivarian Alternative for the Americas (Alba), which includes Venezuela and Bolivia, said on Monday that they would withdraw their ambassadors from Honduras.
Barack Obama, the US president, also criticised the coup.
"We believe that the coup was not legal and that President Zelaya remains the democratically elected president there," Obama said.
However, the US has not legally classified the removal of Zelaya as a coup d'etat as it would automatically lead to the suspension of aid to Honduras, an impoverished nation of 7.2 million people.