However, he added, Hamas would be willing to join forces with current ruling faction Fatah in forming a new government.
"We do not want to replace Fatah," Zahar said, adding that even if Hamas won overwhelming support, all Palestinian factions would be invited to join a coalition government.
"It will not be Hamas alone… Our project is to change the corrupted system, the corrupted regime, to purify the regime," he said.
During the interview, Zahar received a surprising phone call from Palestinian Authority Chairman and Fatah leader Mahmoud Abbas, who called to ask Zahar what he thought of a speech delivered by the Palestinian leader Monday evening.
The Hamas leader told Abbas the speech "was positive and acceptable."
During the interview, Zahar avoided answering whether his group would change its longtime goal of destroying Israel. He also refrained from adderssing warnings by the European Union that it might cut off aid to the Palestinian Authority if Hamas became a part of the government.
'All Israeli leaders are poison'
Zahar also refused to speculate about the effects of Prime Minister Ariel Sharon's illness, saying whoever leads Israel bears the same message.
"They can put the poison in the honey to give it better taste," he said with a smile, but added that "all of them are poison."
Zahar made it clear that Hamas would not give up its weapons, as demanded by international peace mediators, but that as a partner in government it would support the inclusion of all groups in a unified army that would disarm Palestinian clans fighting amongst themselves.
He said a Palestinian army would focus on protecting against what he described as Israeli incursions, like its recent shelling of northern Gaza to create a buffer zone.
"If the aim is to protect the Israeli border, and to put all the guns in the Palestinian factions who are not ready to confront Israel, this will not be acceptable by anybody," he said.
"But if the aim is to put all of the Palestinian guns on the border to protect our institutions, to protect our lands, I think that would be acceptable," he added.
Meanwhile, Zahar did not reject the possibility of renewed attacks inside Israel. He said that Israel had failed to uphold its end of the nearly yearlong cease-fire by assassinating the leaders of other Palestinian factions that have continued attacks, and that it had not met other conditions of the truce.
"For this reason the calmness has ended," Zahar said. "We have the right to self-defense and to protect our people."
'We're different from al-Qaeda'
But he left open the possibility that Hamas might refrain from attacks on Israel "if not provoked."
He added that factional violence may break out on January 25, the Palestinian election date, but that Hamas would work to avoid civil war, which many people in Gaza fear will follow elections.
"The only winner would be Israel," Zahar said.
He also rejected what he described as recent efforts by Israel to draw a connection between Hamas and al-Qaeda.
"Al-Qaeda is not present here," he said. "We are focused on the occupation. We run no operations outside of Palestine, outside of the occupied territories, so we are completely different from al-Qaeda."
Zahar has great plans for the future, after the elections. He said Hamas would try to develop direct trade with the world, cutting out Israel as intermediary, as is now required by an economic protocol signed in 1994 in Paris.
He described that agreement as a disaster for the Palestinians, using the cost of gasoline as an example: It is five times more expensive when imported through Israel than if purchased directly from Egypt, he said.