By John Chalmers and Michael Georgy
ISLAMABAD, May 11 (Reuters) - Pakistanis began voting on Saturday in a landmark election that will bring the first transition between civilian governments in a country ruled by the military for more than half of its turbulent history.
The people of Pakistan hope the polls will deliver change and ease frustrations with a feeble economy, widespread corruption, chronic power cuts and crumbling infrastructure.
Disenchantment with the two mainstream parties appeared this week to have brought a late surge of support for former cricket star Imran Khan, who could end up holding the balance of power if there is no clear-cut winner.
If that happens, weeks of haggling to form a coalition will follow and raise the risk of an unstable government in a country ruled by the military for more than half of its history.
That would only make it more difficult to reverse the disgust with politicians felt among the country's 180 million people and drive through the reforms needed to revive its near-failed economy.
Power cuts can last more than 10 hours a day in some places, crippling key industries like textiles, and a new International Monetary Fund bailout may be needed soon.
Dozens of people have been killed in the run-up to the vote by the al-Qaeda-linked Pakistan Taliban, which regards the poll as un-Islamic and has vowed to disrupt the process with suicide bombings.
"The problems facing the new government will be immense, and this may be the last chance that the country's existing elites have to solve them," said Anatol Lieven, a professor at King's College, London, and author of a book on Pakistan.
"If the lives of ordinary Pakistanis are not significantly improved over the next five years, a return to authoritarian solutions remains a possibility," Lieven wrote in a column in the Financial Times on Friday.
The army stayed out of politics during the five years of the last government, but it still sets the nuclear-armed country's foreign and security policy and will steer the thorny relationship with Washington as NATO troops withdraw from neighbouring Afghanistan next year.
The party of former prime minister Nawaz Sharif looks set to win the most seats in the one-day vote, which gets under way across the country at 8 a.m. (0300 GMT).
However, Khan's dark-horse challenge could deprive Sharif of a majority and dash his hopes for a return to power 14 years after he was ousted in a military coup, jailed and later exiled.
Pakistan's best-known sportsman, who led a playboy lifestyle in his younger days, Khan is seen by many as a refreshing change from the dynastic politicians who long relied on a patronage system to win votes and are often accused of corruption.
THREAT OF ATTACKS
Voters will elect 272 members of the National Assembly and to win a simple majority, a party would have to take 137 seats.
However, the election is complicated by the fact that a further 70 seats, most reserved for women and members of non- Muslim minorities, are allocated to parties on the basis of their performance in the contested constituencies. To have a majority of the total of 342, a party would need 172.
Khan appeals mostly to young, urban voters because of his calls for an end to corruption, a new political landscape and a halt to U.S. drone strikes on Pakistani soil.
The 60-year-old is in hospital after injuring himself in a fall at a party rally, which may also win him sympathy votes.
Early opinion polls had put the share of votes for his Tehrik-i-Insaf (PTI) party as low as single figures. However, a survey released on Wednesday showed 24.98 percent of voters nationally planned to vote for his party, just a whisker behind Sharif's Pakistan Muslim League (PML-N).
The Herald magazine poll showed Sharif's party remained the front-runner in Punjab, which, with the largest share of parliamentary seats, usually dictates the outcome of elections.
It also pointed to an upset for the Pakistan People's Party (PPP), which led the last government, placing it third. Pakistan's politics have long been dominated by the PML-N and the PPP, whose most prominent figure is President Asif Ali Zardari, widower of assassinated former premier Benazir Bhutto.
"The PPP didn't take care of the poor masses and always engages in corrupt practices whenever they come to power," said Sher Nabi, a banker from Peshawar.
"So we've decided to vote for the PTI candidate this time and test Imran Khan to see if he proves as honest as he claims."
In the violence ahead of the election, militants mostly targeted secular-leaning parties in the PPP's outgoing coalition and largely spared more conservative parties that question Pakistan's participation in the U.S.-led campaign against militancy, including those of both Khan and Sharif.
Many Pakistanis still plan to vote despite the bloodshed.
"I want to go out and vote but my parents are scared there will be a bomb or a shooting," said 21-year-old Nargis Fatima, a student in Quetta, one of Pakistan's most volatile cities.
"This is the first time I'm old enough to vote and I'll try my best to go out there and feel that I am part of whatever new set-up comes into place."
(Additional reporting by Mehreen Zahra-Malik in ISLAMABAD, Gul Yousafzai in QUETTA, Mubasher Bukhari in LAHORE and Jibran Ahmed in PESHAWAR)