Hundreds of police were deployed at a Pakistan court in Islamabad on Thursday ahead of the likely indictment of former Prime Minister Imran Khan in a contempt of court case, police said.

The high court is due to indict Khan later in the afternoon, a move that could lead to his exclusion from politics if convicted.

A convicted politician is liable to be disqualified for at least five years under Pakistani laws.

"Over 700 police personnel have been deputed," police officer Kamran Aamir Khan told Reuters outside Islamabad high court where Khan will be appearing.

The contempt charges threaten to end Khan's political career, a day after he announced that his party will begin a countrywide protest campaign to march on capital Islamabad.

The cricket-star turned politician has been facing a spate of legal woes since his ouster in a confidence vote in April by a united opposition led by his successor, Prime Minister Shehbaz Sharif.

Khan has been leading rallies since his ouster demanding snap polls, which the ruling coalition has rejected, saying the elections will be held as scheduled later next year.

The contempt charges are related to a speech by Khan last month in which he allegedly threatened police and judicial officers after one of his close aides was denied bail in a sedition case.

Islamabad police brought up the charges after Khan's public remarks that he would not spare the police and a judicial officer, who had denied bail to his aide.

Khan and his legal team subsequently said that his remarks were not meant to be a threat, but that he would take legal action against the officers. (Reporting by Asif Shahzad; Editing by Frank Jack Daniel)