The Palestinian parliament convened on Monday to consider a motion by Hamas to declare illegal the July 26 referendum over the political document, which implicitly recognises Israel by envisaging a Palestinian state alongside it.
But the resistance group, which formed a government after winning a January election and advocates Israel's destruction, said it would delay lodging the motion until June 20.
This followed a lively series of exchanges, after which deputies voted by a large majority for the continuation of talks.
Mushir al-Masri, a senior Hamas lawmaker, said: "If we succeed through dialogue in stopping the referendum then it will be better, but if we hit a dead end, parliament will assume its responsibilities and hold the vote."
Aziz Dweik, parliament's speaker, said that "we are going to continue our efforts over the coming days and we are hopeful of resolving the whole crisis."
Dweik, a senior member of Hamas, told the start of the session that the referendum had been convened "without any legal basis" and he had written to the central elections commission for its opinion.
Haniya and his Hamas MPs are
contesting the plebiscite's legality
"The law cannot be amended by a presidential decree," added Dweik.
Fellow Hamas MP Anwar Zboun told the chamber that the president, Mahmoud Abbas, did not have the power to call a referendum under the terms of the basic law, the Palestinians' mini-constitution.
"The prerogatives of President Abbas are laid out in the basic law and this law does not give him the power to call a referendum," he said.
Hamas, locked in a power struggle with Abbas, has a parliamentary majority. But there appeared to be little chance that Abbas, a moderate with wide presidential powers, would consider passage of the motion binding.
Among those who were due to speak in the session was Ismail Haniya, the prime minister of the Hamas-led government.
"I am going to take part in the debate in my capacitiy as a member of the PLC (parliament) which is a sovereign body," Haniya said as he arrived at the Gaza City branch of the parliament, earlier on Monday.
Israel not keen
Opinion polls show strong support for the manifesto, penned by Palestinian prisoners in Israeli jails.
Israel has rejected it because of its call for a Palestinian state in the entire occupied West Bank and in the Gaza Strip.
Eight Palestinians died after an
explosion on a beach on Friday
Israel, which quit the Gaza Strip last year, has pledged to hold on forever to parts of the West Bank where major Jewish settlement blocs are. The World Court considers all settlements Israel has built on occupied land illegal.
Abbas announced the vote despite an explosion on a Gaza beach on Friday that killed eight civilians and inflamed passions against Israel.
Palestinians said the deaths were caused by an Israeli artillery shell, but Israel has suggested its army may not be responsible and is conducting an investigation.
Nine more rockets were fired from Gaza towards Israel overnight although they did not cause any injuries and there was no immediate claim of responsibility.
The sharp increase in rocket attacks has led to renewed Israeli threats to assassinate Hamas' leaders.
Tzahi Hanegbi, chairman of the Israeli parliament's Foreign Affairs and Defence Committee, said on Monday that Haniya could become a target if he were to begin directing attacks.
Amir Peretz, the Israeli defence minister, suggested on Sunday that Haniya could be a target, saying that no one involved in attacks against Israel would be immune from retaliatory strikes.