Pakistan's national assembly, or lower house of parliament, is also due to convene later on Monday, ahead of the filing of the impeachment charges against the former general.

Musharraf seized power in a bloodless coup in 1999, but his rivals swept elections in February to set up a new government.

Charge sheet

The governing coalition announced its impeachment plans last week and said it was preparing a "charge sheet" with allegations including violation of the constitution, economic mismanagement and political manipulation.

The coalition had previously been split by the twin issues of what to do about Musharraf and how to carry out their pledge to reinstate senior judges sacked by him under emergency rule last year.

Asif Ali Zardari, the leader of Pakistan's ruling coalition, made the announcement at a news conference in Islamabad, the capital, on Thursday afternoon.

"We have good news for democracy," Zardari said. "The coalition believes it is imperative to move for impeachment against General Musharraf."

"The economic policies pursued by President Musharraf during the past eight years have brought Pakistan to the brink of critical economic impasse," he said.

"His policies have weakened the federation and eroded the trust of the nation in national institutions."

Ahsan Iqbal, spokesman for the second-largest coalition party, Pakistan Muslim League-Nawaz (PML-N), said the impeachment motion will be filed after the provincial assemblies have passed their resolutions, which could continue into next week.

No president has been impeached in Pakistan's turbulent 61-year history. The coalition claims it can get the two-thirds majority required in a joint sitting of both houses in parliament to strip Musharraf of the presidency.

Although Musharraf's allies dispute that and have urged the longtime US ally to fight impeachment, they have advised the president against using his authority to dismiss parliament and the prime minister.

'Corruption and murder'

Farhatullah Babar, a spokesman for the Pakistan People's Party (PPP) of slain former premier Benazir Bhutto, would not comment on reports that the charges due to be finalised on Monday - also Musharraf's 65th birthday - included corruption and murder.

The coalition is trying to give Musharraf time to quit without facing the humiliation of impeachment, while ramping up the pressure with expected "no-confidence" motions in the four provincial assemblies, media reports said.

As the deal to impeach Musharraf emerged on Thursday, the president cancelled his trip to the Beijing Olympics.