Supporters of the Pakistan Peoples Party at a campaign rally in Karachi
Supporters of the Pakistan Peoples Party at a campaign rally in Karachi AFP

Pakistan's politicians hit the campaign trail Tuesday for the last time ahead of a general election that pollsters say has left the nation of 240 million at its most "discouraged" in years.

With former prime minister Imran Khan in jail and his party barred from contesting as a bloc, the field is open for the Pakistan Muslim League-Nawaz (PML-N) to win the most seats and give a fourth term as premier to its founder, Nawaz Sharif.

"The atmosphere... is of a carnival. The elections are a day after tomorrow, but we are already celebrating," Sharif told a rally of around 15,000 in Kasur, south of Lahore in his Punjab province heartland.

Candidates loyal to Khan's Pakistan Tehreek-e-Insaf (PTI) party could still prove a decisive factor -- as well as the Pakistan Peoples Party (PPP) of Bilawal Bhutto Zardari -- but a generally lacklustre campaign season, as well as voter apathy, suggest a low turnout on Thursday.

"The political atmosphere ahead of Pakistan's first general election since 2018 is equally as glum as the economic one," the polling agency Gallup said.

"Seven in 10 Pakistanis lack confidence in the honesty of their elections. While this ties previous highs, it nevertheless represents a significant regression in recent years."

Candidates must end all canvassing on Tuesday night before polls open Thursday for more than 120 million registered voters to take part in an election rights activists have called deeply flawed.

Looming large over the vote -- despite being barred from taking part -- is former international cricketer Khan, who was handed three lengthy prison sentences last week for treason, graft and a marriage that did not meet Islamic law requirements.

The election comes against the backdrop of an economy in dire straits and a significant rise in militancy.

The Pakistan Institute for Conflict and Security Studies, an Islamabad-based think tank, said there had been a "staggering" rise in militant attacks in the past year with an average of 54 per month -- the most since 2015, when the army launched a massive crackdown on militant groups.

At least 10 officers were killed on Monday when militants attacked a police station near the Afghan border in Khyber Pakhtunkhwa province.

Officials said Tuesday that nearly half of 90,000 polling stations had been declared "sensitive" or "highly sensitive" and extra security would be deployed.

"To counter these risks, we have devised a three-tier protection plan. The police constitute the first tier, followed by the civil armed forces, and (then) the armed forces," caretaker Interior Minister Gohar Ejaz told a news briefing.

Inflation is galloping at nearly 30 percent, the rupee has been in free fall for three years and a balance of payments deficit has frozen imports, severely hampering industrial growth.

"Pakistanis are more discouraged than they have been in decades about a multitude of economic, political and security challenges that are threatening their country's stability," Gallup said its poll findings revealed.

"Last year, just one in four approved of Pakistan's leadership."

Frontrunner Sharif, jailed before the 2018 election but freed to seek medical treatment in Britain, returned to Pakistan last year with the blessing of the military-led establishment and has since seen a string of convictions overturned, allowing him to run again.

Tuesday's rally was his final one of the campaign and so he chose to hold it close to Lahore, the capital city of Punjab province -- Pakistan's most populous and home to more than half the national electorate.

A dusty field was transformed into a rally site, with floodlights set up to illuminate the stage and an eardrum-busting sound system that drowned out noise from the surrounding city.

In a bid to sidestep a nationwide crackdown, Khan's PTI has redefined election campaigning in Pakistan with social media rallies and the use of AI technology.

Stripped of its talisman cricket bat logo, the party has launched a mobile phone app that tells voters what logos are associated with its candidates, who are now effectively standing as independents.

Despite party information secretary Raoof Hassan calling it a "non-election", supporters have been urged to vote.

A policeman in Islamabad stands beside a poster urging women to vote in Thursday's election
A policeman in Islamabad stands beside a poster urging women to vote in Thursday's election AFP
The flags of various parties hang over a street in Quetta, southwestern Pakistan
The flags of various parties hang over a street in Quetta, southwestern Pakistan AFP
Workers prepare voting materials for distribution in Islamabad ahead of Thursday's election
Workers prepare voting materials for distribution in Islamabad ahead of Thursday's election AFP