Palestinian Authority President Mahmoud Abbas's Fatah faction's first party congress for 20 years has been extended amid rows between rival camps.
The meeting, which was originally scheduled to last three days, will go on for at least an extra day.
Participants are divided over the process for voting in new members of its powerful central committee.
Younger members want to wrest more control from older leaders seen as corrupt and ineffective.
Nabil Amr, a spokesman for the conference, told local media the second day, Wednesday, was "stormy".
Proceedings have been hindered by a row over the treatment of the votes of about 400 Gaza-based delegates who been prevented from travelling to the congress in the West Bank town of Bethlehem by Fatah's rival faction Hamas.
Hamas controls the Gaza Strip, and refused to allow the delegates to leave unless Fatah released some 900 Hamas prisoners the Islamist movement says are being held in the West Bank.
The Palestinians of course are committed to a peaceful solution, however, we maintain the right for armed struggle when it is necessary and as an option
One proposal is to allow the Gaza delegates to vote via telephone or email, another to allocate a specific number of seats on the committee for the Gaza wing of the faction.
The second option is controversial as it is thought likely to benefit former Gaza security head Mohammad Dahlan, a younger but highly divisive figure.
Delegates seeking to modernise Fatah have also accused the "old guard" of packing the conference with sympathisers to squeeze out younger members.
They accused those who control the Central Committee of adding hundreds of extra delegates to the original list of 1,550.
"They illegally keep adding new members. No one knows the actual numbers," Fatah member Mansuor al-Sadi told Reuters news agency, accusing the committe of "trying to hijack the congress".
A row also broke out when another delegate, Hossam Khader, who has been critical of corruption among Fatah leaders, challenged Mr Abbas to provide a detailed report about the Central Committee's activities in the 20 years since the last conference.
Mr Abbas reportedly told him his lengthy opening speech on Tuesday should suffice and ordered him to sit down.
Charter debate
International interest in the conference has so far centred on whether Fatah will alter its charter, which calls for armed struggle to end the existence of Israel.
This dates back to Fatah's formation in the 1950s by the late Palestinian leader Yasser Arafat.
But by backing the Oslo peace process in the early 1990s, Fatah effectively renounced violence and recognised Israel.
On Tuesday Mr Abbas said Fatah was committed to peace, but maintained armed struggle as an option.
Correspondents say that without major reform Fatah will struggle to restore its image among Palestinians, which will be particularly important if elections scheduled for January 2010 go ahead.
Nonetheless, opinion polls suggest that Fatah is currently more popular than its main rival, Hamas.
It lost Palestinian parliamentary elections to Hamas in 2006.
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