LAHORE, Pakistan - Back in Pakistan from exile, former prime minister Nawaz Sharif was due to file nomination papers on Monday for polls in January but he may not take part unless President Pervez Musharraf ends emergency rule.

Sharif, ousted by Musharraf eight years ago, flew home on Sunday, saying he wanted to help end "dictatorship" in the country that army chief and U.S. ally Musharraf has ruled under emergency powers since November 3.

"General Musharraf has brought this country to the verge of disaster," Sharif told supporters early on Monday during a stop on his slow journey into Lahore from the city's airport where he had landed on a flight from Saudi Arabia.

"We have to save this country. We have to unite and get rid of dictatorship," he said by megaphone from the back of a truck, after a boisterous welcome from thousands of loyalists in his hometown.

Western governments fear Musharraf's emergency rule and moves to stifle democracy in Pakistan could give an advantage to Islamist militants threatening the nuclear-armed nation.

There have been more than 25 suicide attacks since Islamist militants intensified a campaign in July. The latest two killed 15 people in Rawalpindi, near Islamabad, on Saturday.

Musharraf is under pressure at home and abroad to roll back the emergency powers he invoked on November3. He has used them to purge the Supreme Court of judges he feared would annul his October 6 re-election by parliament.

Having now secured a second five-year term, thanks to a new panel of friendly judges, he is expected to quit as army chief and take the oath as a civilian president in the coming days.

Unpopular, politically isolated and desperate for support from the parliament that emerges from the January 8 poll, Musharraf now has to contend with two rivals he has spent much of the last eight years trying to marginalise and called corrupt.

He allowed Benazir Bhutto, another two-time former prime minister, to come back to Pakistan last month protected from old graft charges in the hope she would become a post-election ally.

PRICE OF GHEE

Relations between Musharraf and Bhutto soured almost at once when a suicide attack killed at least 139 at her homecoming parade on October 19.

They worsened after Musharraf called an emergency, sacked judges, detained lawyers, opposition and rights activists, and muzzled the media.

Many of those initially detained have been released, but others have been held since.

Sharif intends consulting with Bhutto's Pakistan People's Party to see if they can work out a common strategy.

Bhutto welcomed Sharif's return, saying she wanted a level playing field for all parties.

The signs are that Bhutto, who filed her nomination papers on Sunday, intends to contest the election.

Sharif party spokesman Ahsan Iqbal said Sharif was expected to file at a Lahore court house, but the party might later withdraw in the event of an opposition boycott.

Musharraf's camp hopes Sharif's party will take part, as a poll without the main opposition parties would lack credibility and ultimately undermine the president, one of Musharraf's close aides told Reuters.

Musharraf co-opted the rump of Sharif's Pakistan Muslim League after ousting him. Leaders of the ruling PML faction fear many of their party may now defect back to Sharif.

Regardless, investors in the Karachi stock market were encouraged by Sharif's return, as they believed it reduced chances of a boycott that could sow more instability. The index rose 0.7 percent on Monday morning.

"It seems the political uncertainty is being lessened every day and now investors are regaining confidence in the market," said Sajjad Mankani, head of sales at BMA Capital Ltd.

The index had shed almost 6 percent since emergency was imposed and has recovered most of its losses and is down only 1.2 percent since then. The index has gained nearly 37 percent since the start the year.

Ordinary folk, too poor to invest, have more to worry about than power plays between Pakistan's movers and shakers.

"Why do we import wheat when we produce ourselves? Why has prices of ghee has gone up from 37 rupees per kg to 105 rupees. The cost of living for poor people is too high," says 56-year-old rickshaw driver Ayub Niazi.