Former Pakistani leader Nawaz Sharif appealed for cross-party support to help rebuild the nuclear-armed but economically crippled nation after winning historic elections that defied Taliban violence.

Partial, unofficial results from Saturday's election represented a stunning comeback for the wealthy 63-year-old tycoon who was deposed as prime minister in a 1999 military coup and spent years in jail and exile.

But Sharif looked short of an outright majority, raising the prospect of coalition rule, as the party of former cricket star Imran Khan achieved its own breakthrough on an anti-corruption platform that resonated with younger voters.

Khan's party was set to take over the provincial government in the restive northwest, where he has vowed to end US drone strikes. Sharif too has tapped into public anger about the missile attacks and pledged peace talks with the Taliban.

Afghan President Hamid Karzai Sunday called on Sharif's incoming government to help negotiate an end to the Taliban insurgency that has ravaged his country since 2001. Pakistan has its own home-grown problem with the Islamist militants.

"We hope that the government paves the way for peace and brotherhood with Afghanistan and cooperates in fighting terrorism and sincerely rooting out terrorist sanctuaries," Karzai said.

Pakistan, which has had three coups and four military rulers, is marking the first time that one elected civilian administration will hand power to another after a full term in office.

TV projections suggested no single party would win an absolute majority in the 342-seat national assembly.

But Sharif's centre-right Pakistan Muslim League-N (PML-N) was well ahead with at least 115 of the chamber's 272 directly elected seats, according to various projections by private channels, and as many as 128 according to Geo TV.

Khan's Pakistan Tehreek-e-Insaf (PTI) was projected to win more than 30 seats, after a high-octane campaign that ended with the former cricketer immobile in hospital after falling at a rally.

The Bhutto clan's Pakistan People's Party (PPP), which led the outgoing coalition government, was trailing in third place as voters punished its record of ineffectual administration over the past five years.

Flanked by his brother and daughter, Sharif gave a victory speech late Saturday to hundreds of jubilant supporters at PML-N headquarters in Lahore.

"We should thank Allah that he has given PML-N another chance to serve you and Pakistan," he said, after nearly 60 percent of the 86 million electorate turned out to vote despite polling-day attacks by the Taliban that left 24 dead.

Sharif, who has vowed a pro-business agenda to revive the feeble economy, struck a conciliatory tone following Khan's emergence as a new powerbroker in Pakistan's clan-dominated politics.

"I appeal for all parties to come to the table and sit with me and solve the country's problems," Sharif said.

The election was defined by the tanking economy, an energy crisis that causes power cuts of up to 20 hours a day, the unpopular alliance in the US-led "war on terror" and chronic corruption.

Prime minister twice before in the 1990s, Sharif's third term will begin only after he brokers a coalition deal with rivals.

Analysts said the PML-N would most likely have to team up with its opponents from the outgoing PPP government.

"(Sharif) needs to solve the issue of terrorism and other problems crippling the economy. If he delivers quickly, fair enough, if not then he will face crisis and criticism," political pundit Hasan Askari told AFP.

But Sharif's supporters hailed a new dawn for the nuclear-armed country. Youths in Lahore danced in the streets holding stuffed tigers -- the PML-N's election symbol -- and people offered each other celebratory sweets.

Chief Election Commissioner Fakharuddin Ebrahim praised authorities for cooperating to allow "free and fair elections" and the highest turnout figure since 1977.

But there were complaints of vote-rigging. Khan's PTI said it would meet later Sunday to look into allegations of ballot fraud including against the PML-N in Punjab, Pakistan's most populous province and Sharif's political heartland.

Besides the national assembly, voters also elected four provincial assemblies in Khyber Pakhtunkhwa, Punjab, Sindh and Baluchistan.

Khan's party emerged on top in the volatile Khyber Pakhtunkhwa province, and PTI member Shaukat Yousafzai said "we will form our government here with the help of like-minded political parties".