The ruling Fatah movement, which has governed for the past decade, will try to play down internal divisions at the launch of its campaign by the tomb of Yasser Arafat in Ram Allah.
While Mahmoud Abbas, the president of the Palestinian Authority, is on a tour of the Gulf states, the deputy prime minister and Fatah's campaign manager Nabil Shaath is expected to address supporters and many of the party's candidates running for office on 25 January.
Meanwhile, Fatah's chief rival, Hamas, will stage its own launch from its Gaza Strip stronghold.
Anti-corruption ticket
Ismail Haniya, who leads the Islamist movement's list of candidates, is expected to address supporters outside the home of the movement's founder, Shaikh Ahmad Yasin, who was assassinated in an Israeli air attack nearly two years ago.
Buoyed by a strong showing in recent municipal elections, Hamas is fielding parliamentary candidates for the first time after boycotting the only previous elections a decade ago.
It is expected to campaign heavily on an anti-corruption ticket, exploiting widespread disillusionment among voters over the perceived incompetence of the current administration.
Abbas's failure to assert control has been sharply illustrated in recent months in the Gaza Strip, where armed men operate above the law and kidnappings are increasingly common.
Four Europeans have been kidnapped in the past week, and the kidnappers of three Britons, who were released unharmed, have threatened to abduct European Union monitors unless a number of demands, including that voting can take place in east Jerusalem, are met.
Dozens of EU monitors have arrived in the major towns to oversee the vote, but say they will be making hourly assessments over the security situation.
Having initially said that the Palestinian residents of occupied east Jerusalem will not be able to cast ballots, Israeli officials, under pressure from the United States, have now said they will contemplate allowing voting.
Internal division
Abbas has said he will call the whole election off if the residents of east Jerusalem are denied the chance to take part in it.
If [east Jerusalem] is not included, [Palestinian] factions are unanimous that there will be no election, he told Aljazeera on a visit to Doha.
Other senior Fatah members, such as the outgoing prime minister, Ahmad Qureia, have demanded that the elections should be postponed because of the security situation and the uncertainty in Jerusalem.
Such demands partly reflect bitterness among the Fatah old guard over the line-up of candidates headed by the jailed intifada leader Marwan al-Barghuthi.
Divisions between the traditional leadership and the younger followers of al-Barghuthi led at one stage to two separate lists being submitted.
Surveys indicate that many voters are still undecided and could yet opt for smaller parties or independent candidates.
Among those who are also launching their campaigns is the rights activist Mustafa al-Barghuthi who came second to Abbas in last January's presidential campaign.