LAHORE: More than 30,000 supporters of Pakistan's main opposition party took to the streets in a protest rally Friday, burning an effigy of President Asif Ali Zardari and demanding that he quit.

The Pakistan Muslim League-N (PML-N) called the rally in Lahore to exploit talk of early elections in its political heartland, where it controls the Punjab provincial government despite being in opposition at national level.

Party faithful denounced corruption and widespread power cuts, calling on the 56-year-old president, to step down before the government's five-year mandate expires in 2013.

Smaller rallies converged into a sea of people, packed left and right for up to two kilometres (one mile), which massed at one of the entrances to the old city of Lahore, witnesses said.

“Go Zardari, go corruption, go load shedding,” they chanted, in reference to the crippling power cuts that blight homes and businesses in much of Pakistan.

Lahore, with a population of eight million, is Pakistan's second-biggest city and the capital of the most populous province Punjab, which commands the greatest number of seats in the national parliament.

That makes it bitterly contested territory where opposition leaders are targeting the unpopular Zardari and trying to whip up future votes.

They are looking to exploit disillusionment with the Pakistan People's Party (PPP) which swept to power in February 2008, two months after Zardari's wife, ex-prime minister Benazir Bhutto, was assassinated.

“Step down Zardari and hand over your money otherwise we will hang you here,” cried Shahbaz Sharif, chief minister of Punjab, addressing the crowd.

His brother, party leader Nawaz, did not attend because he was in Turkey.

After the upcoming Muslim festival of Eid al-Adha, Shahbaz said the party would take to the road leading a nationwide campaign calling for Zardari to go.

An effigy of the president was beaten and seat ablaze, while other followers danced to party songs blasted out at top volume.

Others carried toy lions, the animal is Sharif's election symbol, shouting “Prime Minister Nawaz Sharif, Prime Minister Nawaz Sharif”.

One police official told AFP on condition of anonymity that more than 30,000 people were in the crowd. An AFP reporter earlier estimated 10,000.

Amid tight security, a large stage was set up with bulletproof glass next to hoardings of Nawaz and his brother Shahbaz, chief minister of Punjab.

Police commandos were seen on the rooftops of buildings and Lahore police told AFP officers were on high alert to prevent any possible attack by militants.

Members of Zardari's party have lashed out at the Sharifs, accusing them of misappropriating Punjab's resources for a political rally.

“It was a comedy show and government resources were used to organise it. They used police, health and all other departments to bring people to the rally,” said senior PPP leader and former law minister Babar Awan.

An irritant for both Sharif and Zardari is cricket-hero-turned-politician Imran Khan, who is holding his own rally on Sunday at the Minar-e-Pakistan ground, where the resolution for the creation of Pakistan was adopted in 1940.

Campaigning by his Tehreek-e-Insaf (Movement for Justice) party, which boycotted the 2008 election, has sparked debate about the extent to which he will deprive the Sharifs of political support.