Pakistan's ousted prime minister Imran Khan has showed willingness to withdraw his controversial remarks against a female judge but stopped short of tendering an apology.

During a rally in Islamabad earlier this month, 69-year-old Khan had threatened to file cases against top police officials, election commission and political opponents over the treatment meted out to his aide Shahbaz Gill, who was arrested on charges of sedition.

He had also taken exception to Additional District and Sessions Judge Zeba Chaudhry, who had approved Gill's two-day physical remand at the request of the capital police, and said she should "prepare herself as action would be taken against her."

Hours after the speech, Khan was booked under the Anti-Terrorism Act for threatening police, judiciary and other state institutions at his rally.

A three-member Islamabad High Court (IHC) bench, headed by Justice Mohsin Akhtar Kayani and comprising Justices Babar Sattar and Miangul Hassan Aurangzeb, issued a show-cause notice to Khan and initiated contempt proceedings against him for undermining the integrity and credibility of the judicial system in the eyes of public at large.

The court had also summoned him on August 31.

In a written response sent to the IHC, Khan claimed of not being aware at the time of passing the remarks that Chaudhry was a judicial officer as he was under impression that she was an executive magistrate.

"The respondent (Khan) submits with humility that if the words he uttered is regarded as inappropriate, he is willing to take them back," Khan said in his reply submitted in the court.

Khan, through his attorney, also said that he had not committed any contempt of court and his words at the rally were taken out selectively and blown out of context to give an impression that he was threatening a judge.

"On the contrary, it was the legal right of every citizen to complain about the conduct/misconduct of a judge or any other public functionary in accordance with the law, he maintained.

Finally, he urged that the show-cause notice against him be discharged and contempt proceedings withdrawn.

Since he was ousted from power in April, the cricketer-turned politician has repeatedly claimed that the no-trust motion against him was the result of a "foreign conspiracy".