If convicted, Gilani faces six months in jail and disqualification from office [AFP]

Yousuf Raza Gilani, Pakistan's prime minister, has been charged with contempt of court by the country's supreme court, after he disobeyed a court order to open corruption cases against President Asif Ali Zardari.

Local television channels flashed the news less than half an hour after Gilani arrived on Monday at the courthouse, where he pleaded not guilty.

If convicted, Gilani faces six months in jail and disqualification from office in a case that has fanned political instability and may force elections.

The court's announcement was the formal start to a process that will now take weeks or months to conclude. The next session will be on February 22.

Al Jazeera’s Imtiaz Tyab, reporting from the capital, Islamabad, quoted presiding judge Justice Nasir-ul-Mulk as saying: "Prime Minister Yousuf Raza Gilani wilfully flouted, disregarded and disobeyed the courts".

"Prime Minister Yousuf Raza Gilani wilfully flouted, disregarded and disobeyed the courts"

- Justice Nasir-ul-Mulk, presiding judge

The judge then went on to underline why under the constitution of Pakistan, the prime minister was being charged, our correspondent said.

"Now, we are going to see his legal defence submit their arguments as to why they don’t believe the prime minister should be charged with contempt of court," Tyab added.

"The lawyer representing the prime minister, Aitzaz Ahsan, has asked to reappear in front of the court in 11 days time, but the fact remains that Pakistan’s longest serving prime minister has been charged with contempt of court."

The supreme court had insisted that Gilani appear for the framing of contempt charges over the government's two-year refusal to ask Swiss authorities to re-open graft cases against the president.

Gilani has said corruption charges against Pakistan's president were "politically motivated" and that the president had immunity as head of state.

The court on Friday threw out a last-ditch appeal from the embattled prime minister, saying it would only drop the summons if Gilani obeyed its order to write to the Swiss authorities, asking them to re-open the cases.

Political amnesty

Gilani has said that if convicted he will lose his seat in the parliament and will automatically be removed as prime minister.

"Certainly then there is no need to step down if I am convicted, I am not supposed to be even the member of the parliament," Gilani told Al Jazeera in an interview last week.

Gilani himself appeared before the Supreme Court on January 19, citing Zardari's immunity as explanation for his refusal to obey the court's order.

Zardari and his late wife, Prime Minister Benazir Bhutto, were accused of using Swiss bank accounts to launder about $12m in alleged bribes paid by companies seeking customs inspection contracts in Pakistan in the 1990s.

The Pakistani court overturned in December 2009 a two-year political amnesty that had frozen the allegations against Zardari and other politicians.

The Swiss shelved the cases in 2008, when Zardari became head of state, and a prosecutor in Switzerland has said it will be impossible to re-open them as long as he remains head of state and is immune from prosecution.

The president, who is so tainted by corruption allegations that his nickname is "Mr 10 per cent", has already spent 11 years in jail on charges ranging from corruption to murder.

He was never convicted and his supporters say that the charges were politically motivated.

Source: Al Jazeera and agencies