Supported by the ruling PML-Q, Musharraf, who seized power in a bloodless military coup in 1999, is projected to win the approval of the national and provincial assemblies, which constitute the electoral college.

A day before the poll, the Supreme Court hearing petitions against Musharraf's candidature said the election can go ahead as scheduled but the result should not be announced till it decides on the matter.

The polling for the presidential election will be held simultaneously at Parliament House here and the provincial assemblies of Punjab, Sindh, North West Frontier Province and Balochistan. The electoral college will vote under the secret ballot system.

Special sessions of Parliament and the provincial assemblies have been convened for the polling, which will be done between 10 am and 3 pm.

Chief Election Commissioner Qazi Mohammad Farooq, who will preside over the session at Parliament House, can extend the polling time under special powers delegated to him.

There was tight security at the Parliament House, with every person entering the premises being checked by security personnel deployed in the area.

Ex-Premier Benazir Bhutto-led Pakistan People's Party (PPP) candidate Makhdoom Amin Fahim and Wajiihuddin Ahmed, a former Supreme Court lawyer who has been nominated by the lawyers' community, are challenging Musharraf in the poll.

Fahim was fielded by PPP despite the party having power-sharing talks with Musharraf's representatives.

About 200 opposition lawmakers from national and provincial assemblies have already resigned in protest against Musharraf's re-election bid.

Bhutto also said in London on Friday that although her party would take part in the election, it would not vote as it would legitimise the General's candidature.

Musharraf had last month given an undertaking to the Supreme Court that he would shed uniform if re-elected. He has already appointed Lt Gen Ashfaq Pervez Kiyani, till recently the head of ISI, to succeed him as the Army Chief when he steps down.

Pakistan is on a high security alert for the presidential election amid fears of a militant backlash against the General, who is being targeted by al-Qaeda for his crackdown on them.

Special security arrangements have been made by the Capital Territory Administration and provincial governments to ensure the smooth conduct of polling

Ahead of the poll, Musharraf signed a reconciliation ordinance yesterday paving the way for a power-sharing deal with Bhutto, a move apparently aimed at giving credibility to his re-election bid.

Under the ordinance, Bhutto, who has vowed to return home on October 18, and other political leaders -- except exiled former Premier Nawaz Sharif -- will get the immunity in all court cases against them.