ISLAMABAD (AFP) - A Pakistani accountability court on Friday dismissed two long-standing corruption cases against Prime Minister Nawaz Sharif and his family, calling them politically motivated and without merit.

The decision comes at a time when Mr Sharif is under pressure from a protest movement led by opposition leader Imran Khan and a populist cleric, who have accused the government of massive corruption in addition to election rigging.

The cases related to the building of Mr Sharif's palatial Lahore home from allegedly unknown sources of money, and laundering charges through his Hudabiya paper mill company.

They were brought to court by the government of former military ruler Pervez Musharraf in 2000, a year after he deposed Mr Sharif in a bloodless coup.

Officials said that the National Accountability Bureau (NAB), the state watchdog for graft requested the court on Friday to allow it to reinvestigate the graft cases against Mr Sharif.

But Judge Anwar Ahmed Khan observed that these cases were pending for more than a decade and asked the prosecutor why no progress had been made, before dismissing them.

"The court dismissed the request by NAB and has acquitted all the persons nominated in the cases," an accountability official told AFP.

Ahmed Junaid, lawyer for Mr Sharif said that the court will hear another graft case related to Mr Sharif's Ittefaq steel mills on Oct 2.

Mr Sharif's brother Shahbaz, who is the chief minister of Punjab province, was also implicated in the graft cases.

In addition to levelling the corruption charges, Musharraf's government confiscated assets worth some US$5 million at the time, five residential plots and 24 hectares of agricultural land belonging to Mr Sharif and his family.

Mr Sharif returned to Pakistan in 2007 and was runner up in 2008 general elections. He became prime minister last year after his Pakistan Muslim League won a majority in the poll.