Tahirul Qadri, who drew scores of supporters to a sit-in protest in Islamabad in January last year, is due to arrive a week after eight people were killed when his followers clashed with the police in of Lahore.
His return could add to the pressure on Prime Minister Nawaz Sharif's government at a sensitive time when the country's military is engaged in a major offensive against militants in North Waziristan.
Qadri has a large following in Pakistan but some analysts believe he is also supported by the country's powerful military establishment to keep civilian authorities in check.
Security was tight in Islamabad ahead of his arrival, with the government deploying armed personnel at all entry and exit points of the capital and blocking roads leading up to the airport with shipping containers.
A spokesman for Civil Aviation Authority told AFP Qadri's flight had been diverted to Lahore "to ensure the safety of the passengers and aircraft".
But Qadri's supporters, including a large number of women, managed to breach police cordons to arrive at the Islamabad airport overnight, chanting "Long live Tahir-ul-Qadri" and "revolution, revolution, Islamic revolution".
Surveillance helicopters flew overhead as police fired teargas at the crowd occupying the area outside the airport, an AFP reporter at the scene said.
Television footage showed Qadri's followers armed with sticks and bricks clashing with baton-wielding police.
Qadri had led the last protest for over four days during the tenure of the Pakistan Peoples Party (PPP) government four months before the May 2013 general election.
He had demanded the early dissolution of the government and implementation of a caretaker setup backed by the military and judiciary.
But despite intense media interest, the protest had little long-term impact -- Qadri ended his sit-in after talks with ministers and the election went ahead as planned.
Qadri is the founding leader of Minhaj-ul-Qur'an International (MQI), an organisation with branches in more than 90 countries and that works for the promotion of peace and harmony between communities.
His sudden and apparently well-financed emergence after years living in Canada was criticised as a plot by sections of the establishment -- particularly the armed forces -- to delay the elections and regain power.
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Upfront Qadri talks about "corruption," "terrorism," "nepotism" but that actually are well accepted slogans. However, Qadri's real objective is to use these issues to overthrow the govt and bring about a non-Deobandi dispensation.
@Not Surprised: Braelvis are a majority in Pakistan as a whole but a proactive minority which is well-connected, powerful, and is well represented in the officer cadres of the Army could very well be maneuvering to subdue the present dispensation or to overthrow it.
Not a revolution but Qadri seems to be paving the way for a coup d’état.
@SHAH:
Braelvis are in majority but not dominant.
The clashes, it should be noted, are between a peaceful organisation of unarmed people and terrorist state entities who demonstrated no regard for human life when they killed innocent people in Lahore last week.
@Not Surprised .. Sindh and Southern Punjab be a shia state where Braelvi are dominant ..
If Qadri succeeds in toppling the Government, Pakistan is likely to become a splintered state. Punjab might become a Braelvi entity, and the Mosal of Pakistan could very well be in Hazara as Sindh and Southern Punjab is likely to become a Shia state. Hazara and part of KP are likely to become a Deobandi entity. Part of south-western Baluchistan might become part of Iran, while northern Baluchistan might join Afghanistan.