The petitioner said prime minister Imran Khan criticised senior judges of the Supreme Court.

A petition has been filed in a Pakistani court seeking disqualification of Prime Minister Imran Khan for his "anti-judiciary" remarks on the departure of his political rival and former premier Nawaz Sharif to London for treatment.

Tahir Maqsood, a Pakistani citizen, filed the petition in the Lahore High Court on Saturday, seeking contempt of court proceedings against Mr Khan for bringing the judiciary into disrepute.

The petitioner said the prime minister criticised senior judges of the Supreme Court which amounts to contempt of court.

He said the Supreme Court in 2013 had already issued a contempt notice to Khan for his anti-judiciary rants.

Referring conviction of PML-N leaders Talal Chaudhry and Nehal Hashmi by the Supreme Court for their anti-judiciary speeches, the petitioner requested the court to summon Khan in person, disqualify him and order the Election Commission to de-notify him as member of the National Assembly.

Mr Khan recently criticised the Lahore High Court for overruling his government's condition for 69-year-old Nawaz Sharif to submit a Rs 700 crore indemnity bond for permission to fly abroad for treatment and asked Chief Justice Asif Saeed Khosa and his successor to "restore the public''s trust in the judiciary."

His remarks did not go down well with the chief justice, who said the prime minister should refrain from issuing such statements as he is the chief executive of the government.

"Do not taunt us regarding the powerful," the chief justice said, adding that everyone is equal before the law.

"I do not want to comment on the particular case of Nawaz Sharif, which the prime minister had referred to but he (the prime minister) will be aware that he himself gave Nawaz permission to go abroad. The premier should refrain from making such statements...Don''t compare us with the judiciary which had existed before 2009," Mr Khosa said.

Imran Khan in a public address cast a doubt over the veracity of medical reports on the health Sharif, saying he was shocked to see the way Sharif ran up the stairs of the air ambulance.

Nawaz Sharif left for London on November 19 and currently is undergoing different tests out there for diagnosis of his disease.

Khan said that Sharif's medical reports listed 15 diseases, including cardiac complications, which suggested that the ex-premier was on the verge of demise.

"But after seeing Nawaz board the air ambulance, I wondered if the former prime minister got healthy with the first glance of the London-bound airplane," Imran Khan said.

Imran Khan had earlier declared that his government allowed Sharif to travel to London on "humanitarian grounds" and on the recommendations of the medical board.

Nawaz Sharif's party PML-N reacted angrily over Mr Khan's remarks and declared him mentally unfit to rule the country. "As your performance is zero you (Khan) have become mentally unstable and a liability of this country," PML-N spokesperson Marriyum Aurangzeb said.

She also urged that Imran Khan must be tried on hate speech charges and demanded his medical check-up.