Pakistan's ousted prime minister, Nawaz Sharif, has been accused by police of planning to escape from prison along with two accomplices.

Nusrat Hussain, superintendent of Landhi prison in Karachi where Mr Sharif is held, has filed a complaint at a local police station, according to agency reports.

Mr Sharif's former Accountability Bureau chief, Saif-ur Rehman, and former Pakistan International Airlines head, Shahid Khaqan Abbasi were also named.

"These three people prepared the jail break plan," chief public prosecutor Raja Qureshi said.

Police allege that a map of the jail was found in possession of Mr Rehman's daughter, when she left Landhi prison after visiting her father earlier this month.

Denial

Raja Qureshi said if found guilty, Mr Sharif and his associates could face a 10-year prison sentence.

"Since these are not scheduled offences, the case of jail break would be tried in normal courts and not in the special anti-terrorism courts," Mr Qureshi said.

But a lawyer for the deposed premier, Arshad Khan Jadoon, said Mr Sharif was innocent.

"It is a lie. The former premier Mian Nawaz Sharif does not need to plan for a jail break when he is already facing charges in the court," Mr Jadoon said.

"It is just an attempt to humiliate the political leader. He is innocent and does not need to run away from the prison," he said.

Mr Sharif has been formally charged with hijacking, attempted murder, terrorism and kidnapping.

The charges relate to events last October, when Mr Sharif was overthrown in a military coup by General Pervez Musharraf.

Mr Sharif is said to have refused to allow a plane carrying General Musharraf and 200 passengers permission to land, thus endangering the lives of those on board.