Campaigning has been stepped up for the Palestinian presidential elections, due to take place on 9 January.
Abbas spoke in the shadow of the Israeli barrier
Fatah candidate Mahmoud Abbas called on Israel to dismantle its West Bank barrier at a rally in Tulkarm.
Meanwhile, the left wing Popular Front for the Liberation of Palestine has thrown its weight behind human rights activist Mustafa Barghouti.
Polls suggest Mr Abbas is leading the race by a significant margin with Mr Barghouti in second place.
PLO chairman Mr Abbas - also known as Abu Mazen - told thousands of supporters at the rally in the West Bank town of Tulkarm that no barrier would bring Israel peace or security.
"If the Israelis want to reach a fair and just peace, they will take down the wall," he told the crowd at a football stadium, just yards from the 8m-high (25ft) concrete slabs of the structure itself.
The barrier is built to the west and north of Tulkarm and is planned to run for 700km (440 miles) throughout the West Bank.
Israel says the barrier is aimed at preventing suicide bombers, but Palestinians say its route - snaking deep into their territory - makes it an illegal land grab.
The International Court of Justice has ruled that the barrier violates international law and urged the United Nations to take action to stop its construction.
Mr Abbas also reiterated his call to establish an independent Palestinian state in the West Bank and Gaza through negotiations and a fair solution for refugees displaced after the creation of the state of Israel in 1948.
The Popular Front for the Liberation of Palestine (PFLP) called on its supporters to vote for human rights campaigner Mustafa Barghouti.
Barghouti has sometimes found campaigning an uphill struggle
The endorsement of the left-wing organisation increases Mr Barghouti's chances of finishing second in the poll.
The PFLP had boycotted the last Palestinian presidential elections in 1996.
Mr Barghouti was arrested by Israeli police whilst campaigning in East Jerusalem on Monday, according to his aides.
Two Palestinian presidential candidates are also yet to receive permission from Israel to leave the Gaza strip to campaign in the West Bank, the AFP news agency has reported.
Sayyed Baraka and Abdelkarim Shubeir are still waiting for permission despite Israeli pledges to ensure the free movement of candidates, the agency said