Pakistani ministers held talks Thursday with a cleric leading a mass protest in Islamabad in an attempt to avert a political crisis and end a demonstration that has heaped pressure on the fragile government.

A decision by the Supreme Court to defer a case of alleged corruption against Prime Minister Raja Pervez Ashraf, after officials claimed not to have enough evidence to arrest him, seemed to give the government some breathing space.

Tension has been at fever pitch since Tuesday, when the court ordered Ashraf's arrest and cleric Tahir-ul Qadri poured into Islamabad with tens of thousands of supporters, denouncing politicians and praising the armed forces and judiciary.

The timing sparked panic about a rumoured judiciary-military plot to derail elections due by mid-May. The polls, if successful, would be the first democratic transition between two civilian governments in Pakistan's history.

The crisis comes as Pakistan battles problems on numerous fronts: the economy is struggling, Taliban and other violence is at a high, the rupee is sinking, there is an appalling energy crisis and fledgling peace gains with India appear in jeopardy following five cross-border killings in a week.

Qadri signalled that his protest in Islamabad would end on Thursday and invited the government to last-minute talks.

At around 4 pm (1100 GMT), a delegation of cabinet ministers and members of the coalition entered the bullet-proof container, where Qadri has been holed up for days on the main commercial avenue near parliament.

Information Minister Qamar Zaman Kaira, who was part of the delegation, said the talks would try to resolve the situation, which has paralysed part of the city.

Qadri's supporters, who have braved cold weather and heavy rain to camp out since overnight Monday-Tuesday, broke into cheers and danced in the street at news of the dialogue.

Most were shivering with cold. Some were drying their clothes after the rain stopped and the sun came out, an AFP reporter said.

"You keep sitting here until the dialogue succeeds, a formal agreement is written and it is announced. Don't move until then," Qadri told them.

"Congratulations. The voice of the people has been heard. We will leave here after victory."

Qadri wants parliament dissolved immediately and a caretaker government set up in consultation with the military and judiciary, to implement reforms before free elections can be held.

The government has so far stuck to its position that parliament will disband in mid-March to make way for a caretaker government, set up in consultation with political parties, and for elections within 60 days -- sometime by mid-May.

Qadri has announced that Thursday would be the last day of the sit-in. "Tomorrow there will be no sit-in. We have to end it today," he added.

His sudden -- and apparently well-financed -- emergence after years living in Canada has been criticised as a ploy by sections of the establishment, particularly the armed forces, to delay the elections and regain power.

The military has remained silent during the protest and President Asif Ali Zardari has stayed in the financial capital Karachi.

Chief Justice Iftikhar Muhammad Chaudhry adjourned until January 23 the case being heard against Ashraf and 15 others accused of corruption over power projects.

Chairman of the National Accountability Bureau Fasih Bokhari said the investigation was not yet complete and it would take take to find evidence to prosecute those allegedly involved.

Chaudhry ordered Bokhari to report back next week, having previously told him to bring the case files so that the court could itself point out evidence.

The court in March 2012 had ordered legal proceedings against Ashraf, who was water and power minister when the power projects were set up.