But he did not say when he was planning to cross the border and enter Honduras, Sanchez said.
The military-backed interim government has said that Zelaya will be arrested if he enters the country.
"The executive branch, the judiciary and congress can't all be wrong [on Zelaya's removal from power]"
Valentin Suarez, the head of Honduras' ruling Liberal Party in congress
"There is an arrest order and if Mr Zelaya enters we will proceed according to the law and arrest him," Daniel Molina, spokesman for the security ministry, said.
Zelaya has promised on several prior occasions to return to Honduras to challenge the interim government, which is led by Roberto Micheletti.
The latest pledge comes a day after President Oscar Arias of Costa Rica, the mediator in emergency talks between delegates for Zelaya and Micheletti, called for the interim government to reinstate Zelaya in exchange for an amnesty for the coup leaders.
Arias' final set of proposals also called for Zelaya to drop efforts to reform the Honduran constitution, a move which sparked the military-backed coup against him.
The Micheletti camp said that they would put the proposal to the Honduran congress, but it is unlikely that legislators will agree to Zelaya's return as president.
"The executive branch, the judiciary and congress can't all be wrong," Valentin Suarez, the head of Honduras' ruling Liberal Party in congress, said.
"It is a crazy recommendation for Hondurans."
But Jose Miguel Insulza, secretary-general of the Organisation of American States (OAS) said on Thursday that he hoped the two sides would reach an agreement.
Neither delegation had responded officially to Arias' final proposal, he said.
Zelaya was removed from power as he was about to press ahead with a non-binding referendum that critics said was aimed at changing the constitution to enable him to run again for office.
Zelaya said the charter changes were necessary to improve the lives of the poor.