Congress head Jose Alfredo Saavedra said deputies could not rule on Zelaya's return, part of a plan by Costa Rican President Oscar Arias to end the Honduras crisis, because it was a constitutional question.
The United States insisted on Monday it wants Zelaya reinstated but made no commitment to tightening sanctions to put pressure on the de facto government that replaced the leftist leader after a June 28 coup.
The coup in Honduras, an impoverished exporter of textiles and coffee, is Central America's worst political crisis in two decades and a test of U.S. President Barack Obama's commitment to improving relations with Latin America.
Zelaya, an ally of Venezuela's socialist President Hugo Chavez, was ousted as he sought a referendum vote to change the constitution to extend presidential term limits -- a move the Supreme Court said was unconstitutional.
Zelaya is now in exile in neighboring Nicaragua.
The Honduran Congress did create a committee on Monday to study some elements of Arias' proposal, including an amnesty for political crimes that would cover Zelaya, and it was expected to reach a decision by Thursday, Saavedra said.
Talks between the rivals in Honduras ran into trouble last week over the question of Zelaya's return as president, a condition that de facto leader Roberto Micheletti and his supporters have said is impossible and illegal.
Micheletti said he would nevertheless consult Congress and the Supreme Court over whether Zelaya can return.
A Supreme Court source said the court had considered the proposal on Monday but there was no word on when it would announce a judgment.
No foreign country has recognized the de facto government but Micheletti has so far refused to back down, apparently gambling he can hold out until November elections and the world will accept the new order after that.
ZELAYA WANTS MORE FROM U.S.
Obama has condemned the coup, cut military aid to Honduras and thrown his support behind the Arias plan. But Zelaya complained on Sunday that Washington is wavering and has not done enough to win his reinstatement.
Zelaya went to the border and took a few symbolic steps on Honduran soil last Friday, a gesture criticized by U.S. Secretary of State Hillary Clinton as reckless.
The U.S. government said it had not changed its position.
We want the restoration of democratic order and that includes the return by mutual agreement of the democratically elected president, and that's President Zelaya, State Department spokesman Ian Kelly said in Washington on Monday.
The de facto government has refused to let Zelaya back in and says it will arrest him if he does return. Zelaya complains that Clinton has stopped using the term coup to describe his removal from power on June 28.
The position of Secretary Clinton at the beginning was firm. Now I feel that she's not really denouncing (it) and she's not acting firmly against the repression that Honduras is suffering, he told reporters over the weekend.
Asked if the United States would impose new sanctions on the de facto government in Honduras, Kelly said Washington wanted to give Arias more time to seek a negotiated solution.
We're content to let that process play out. We're not going to put any artificial deadline on that, he said.
Seeking to win over his critics and perhaps avert harsher U.S. sanctions, Micheletti wrote an article in the Wall Street Journal on Monday arguing Zelaya's removal was legal because he was seeking to extend presidential term limits.
The truth is that he was removed by a democratically elected civilian government because the independent judicial and legislative branches of our government found that he had violated our laws and constitution, said Micheletti, chosen by Congress to lead the country hours after Zelaya was ousted.
Micheletti said he understood criticism of the abrupt way that Zelaya was ousted.
Reasonable people can believe the situation could have been handled differently, he said.
But it is also necessary to understand the decision in the context of genuine fear of Mr. Zelaya's proven willingness to violate the law and to engage in mob-led violence.
(Additional reporting by Marco Aquino, Esteban Israel, Gustavo Palencia and Sean Mattson in Honduras, Ivan Castro in Nicaragua, Tim Gaynor in Washington; Writing by Claudia Parsons; Editing by John O'Callaghan)