Pakistan will go to the polls on 11 May, the presidency announced Wednesday, in an historic general election marking the first democratic transition of power in the country's 66-year existence.

President Asif Ali Zardari, who confounded critics by keeping his fractious coalition together for a full five-year term, announced the date days after the 342-member national assembly dissolved at the end of its term.

"The president announced today that general elections to the national assembly will be held on 11 May," his spokesman Farhatullah Babar told AFP.

The vote will mark the first time that an elected civilian government hands over to another in a country that has seen three military coups and four military rulers since partition from India and the end of British rule in 1947.

But Taliban attacks and record levels of violence directed against the Shiite Muslim minority have raised fears about security for the polls in the nuclear-armed country of 180 million, a key but troubled US ally.

A parliamentary committee has until Friday to select a candidate to head a caretaker administration until the polls. The election commission should then announce a full schedule for the campaign.

Zardari's Pakistan People's Party (PPP) and the opposition Pakistan Muslim League-N led by former prime minister Nawaz Sharif are likely to dominate the race, while former cricket star Imran Khan will compete in an election for the first time.

Bilawal Bhutto Zardari, the son of Zardari and of assassinated former Prime Minister Benazir Bhutto, is co-chairman of the PPP but cannot stand because he will not reach the minimum age of 25 until September.

Separate elections will also be held for regional assemblies in Pakistan's four provinces. Punjab on Wednesday became the last to dissolve, setting the scene for probable provincial elections on 11 May as well.

"For five years we tolerated the government with patience for the sake of democracy," Sharif told reporters at his family's sprawling estate just outside Lahore.

He urged the people of Pakistan to "rejoice" at the prospect of a democratic transition, adding: "We have to strengthen democracy. Martial law is not a solution, it is the cause of many ills."

Sixty seats in the national assembly are reserved for women and 10 for non-Muslim religious minorities.

Under reforms introduced by the outgoing government, political parties can for the first time contest elections in the tribal belt, a den of Taliban and Al-Qaeda militants on the Afghan border.

But there are no seats in the tribal belt reserved for women.

Once the national and provincial governments are formed, federal and regional lawmakers will elect a new president.

Analysts praise Zardari for lasting the course, passing key legislation and relinquishing his powers to strengthen democracy, but say his rule has been marked by chronic mismanagement, economic decline and worsening security.

They credit his full term not just on his wheeler-dealer talents, but also on the army chief of staff's determination to keep to the sidelines and the opposition's unwillingness to force early elections.

Apart from a military operation that pushed the Taliban out of the Swat Valley in 2009, the government has failed to crack down on the plethora of extremist groups blamed for violence in Pakistan, Afghanistan and India.

Pakistan has hosted no international sport since gunmen attacked the Sri Lankan cricket team in 2009. Religious violence has reached dizzying levels, most recently against Shiites, who account for about 20 percent of the population.

Karachi, the largest city and business hub, is suffering from record killings linked to political and ethnic tensions, with more than 2,000 dead in 2012.

The government has also done little to come up with long-term solutions to a crippling energy crisis or introduce desperately needed tax reforms. Ministers have been tainted by accusations of brazen corruption.

After the elections, Pakistan is expected to have little option but to seek another bailout package from the International Monetary Fund, given its yawning budget deficit.