The Islamist group Hamas has captured 76 of 132 seats in the Palestinian parliament, according to near-total election results.

The Fatah party – which had dominated Palestinian politics for decades under Yasser Arafat and then Mahmoud Abbas – won only 43 seats, the Central Election Commission said in Ramallah on Thursday.

"Today we woke up and the sky was a different colour," said Saeb Erekat, a Fatah legislator who has been the chief negotiator for the Palestinians.

"We have entered a new era."

The senior Hamas leader in the Gaza Strip, Ismail Haniyeh, said the victory showed that Palestinians were fed up with Fatah and its peace overtures with Israel, which controls Palestinian areas in the West Bank.

"This is a victory of the Palestinian people who voted against the occupation, who voted for resistance, who voted for a new political system based on political partnership," Haniyeh said.

The Hamas victory immediately raised concerns about the prospects for peace in the Middle East. The group includes in its charter a commitment to the destruction of Israel and has carried out dozens of suicide attacks against Israelis in the past five years. Israel, the United States and the European Union have all listed Hamas as a terrorist organization.

However, analysts said the group's militant stance lured fewer voters than its strong anti-corruption platform, its promise to restore order in Gaza and the West Bank, and its widespread health and social-service networks in the Palestinian territories.

Some Palestinians predicted Hamas would moderate its position about Israel once in power, noting that Fatah was also once sworn to the destruction of Israel. They pointed out that the armed wing of Hamas mostly honoured a year-old ceasefire with Israel.

A top Hamas official, Mahmoud Zahar, said on Thursday it would extend the truce if Israel reciprocates.

"If not, then I think we will have no option but to protect our people and our land," Zahar said.

But another prominent Hamas leader indicated that official political power wouldn't change its key positions, the Associated Press reported.

"Negotiations with Israel is not on our agenda," said Mushir al-Masri, who won election in the northern Gaza Strip. "Recognizing Israel is not on the agenda either now."

Hanna Nasser, head of the Central Election Commission, said the results could change slightly but were based on a count of 95 per cent of the votes in Wednesday's election.

Turnout was about 78 per cent of about 1.3 million voters. Exit polls showed Hamas had earned about 46 per cent of the popular vote, compared to about 40 per cent for Fatah.

Reports of a sweeping Hamas victory sparked brief clashes between the militant group's supporters and Fatah loyalists outside the legislature in Ramallah.

About 3,000 Hamas supporters gathered in front of the parliament while some rushed inside and raised their green banner on the roof of the building. Fatah loyalists tried to lower the flags while supporters from both groups threw stones at each other, breaking windows.

Later, thousands of Hamas supporters celebrated peacefully in the streets of Gaza.

The Hamas victory doesn't automatically oust Abbas, who was elected as president of the Palestinian Authority after Arafat died in 2005. However, he said earlier that he would step down if he felt he was unable to continue pursuing peace with Israel.

Before the official election results came in, Prime Minister Ahmed Qureia said he and all his cabinet ministers were quitting. Under Palestinian law, the party that holds the most seats in parliament can shape the cabinet and veto the president's choice of prime minister.

Khaled Mashaal, who is the top leader of Hamas and lives in exile in Syria, called Abbas to discuss the election results and floated the possibility of a coalition government.

"He stressed Hamas insists on a partnership with all the Palestinian factions, especially our brothers in Fatah," Hamas said on its website.

But a Fatah spokesman said Fatah would choose to form an opposition rather than join a coalition.

"We will be a loyal opposition and rebuild the party," Erekat told the AP after meeting with Abbas.