Pakistan's wildcard politician Imran Khan says he is happy to go into opposition if his "tsunami" of popular support fails to bring him a landslide victory at elections now widely expected within months.

The 59-year-old former cricketer has ridden a wave of support buoyed by mass rallies and has openly backed the courts' pursuit of embattled President Asif Ali Zardari and Prime Minister Yousuf Raza Gilani.

But in an interview with AFP at his hilltop villa outside Islamabad, Khan admitted that his fledgling Movement for Justice could suffer if a series of crises force general elections earlier than September or October.

"The 'tsunami' is ready. We will be ready. Obviously it suits our party... if this government goes for another six months," he said.

Under the Pakistani constitution, a government resigns in favour of an administration of technocrats for up to three months before a general election.

If the current government collapses earlier than the summer, Khan could see his popularity -- built on the back of nationalist rhetoric delivered with messianic zeal and rousing musical performances -- put to a premature test.

"We would happily go into the opposition if we can't form a government because basically it's a battle between forces of status quo and forces of change," Khan told AFP.

Speculation is widespread in Pakistan that Khan's party is being quietly groomed by the powerful military, which are believed to back moves in the courts to chip away at Zardari and Gilani's authority.

"I think it's the endgame because the government -- it's been openly defying the Supreme Court," said Khan.

"I don't think the Supreme Court is going to back down. They've called the prime minister dishonest so really in any decent democracy he should have resigned by now and then asked to go back to the people."

But he added: "No one wants martial law in this country, none of us want it. I think the time for martial law is over in Pakistan."

Khan insists his relationship with the generals is a "sensible" one that would put him clearly in charge should his party sweep to power.

"If I'm the prime minister, if I have the responsibility, I have the authority," he said.

Predictions for early polls have inched forward as tensions have risen between the prime minister and army, and with the Supreme Court now holding Gilani in contempt of court.

The contempt order given by judges adjudicating corruption claims leaves the government's fate perilously unclear.

Analysts say that however it plays out, momentum is building for early elections, officially due at the beginning of 2013, but now believed more probable in either April or September-October.

Khan rules out forming a coalition with any of the "status quo" parties he considers venal and corrupt -- Zardari's Pakistan People's Party or opposition PML-N led by former prime minister Nawaz Sharif.

Instead he is confident that his prescription for Pakistan -- unbuckling the country from the US-led war on terror alliance with the United States by refusing foreign aid and launching a massive austerity drive, will succeed.

But political commentators say Khan's vision of a united Pakistan free from mafia and liberated from foreign influence is a pipe dream playing to a receptive crowd as the country faces renewed political uncertainty.

Malaysia, Turkey, South Africa and even Scandinavia are cited as models of inspiration for Khan and among the youth, his message is being widely embraced.

"He is giving them dreams, dreams for the future," said Hasan Askari. "But we don't know whether he will be able to realise those dreams."

Journalist Najam Sethi said Khan's message feeds the mindset of the majority of disaffected lower middle class Pakistani voters -- conservative, Muslim and increasingly anti-American.

"He is, shall we say, the most articulate anti-American shrill voice in this country -- number one. Number two, Imran is also now pandering to certain religious symbols," Sethi said.

Khan's next rally is planned for March 23 in Quetta, capital of restive Baluchistan province, which is wracked with separatist violence and mass deprivation.