ISLAMABAD (REUTERS) - The chief of the Pakistani government's anti-corruption department on Thursday rejected a Supreme Court order to arrest the prime minister, television channels reported, providing some relief to a government gripped by political turmoil.

On Tuesday, the court ordered the arrest of Raja Pervez Ashraf in connection with alleged kickbacks in transactions involving rental power plants when he served as power minister.

Fasih Bokhari, head of the National Accountability Bureau, told the Supreme Court that investigations of the allegations against Ashraf were incomplete, local television channels reported.

The court asked Bokhari to produce case records so that it could decide whether there is enough evidence to prosecute the prime minister and other officials accused in the case.

The administration is already facing pressure from fiery cleric Muhamad Tahir ul- Qadri, who has fired up thousands of protesters camped outside parliament with his calls for the resignation of political leaders and electoral reforms.

Qadri, who backed a military coup in 1999, is calling for the immediate resignation of the government and the installation of a caretaker administration in the run-up to elections this spring.

His appearance at the forefront of Pakistan's political scene has fuelled speculation that the army, which has a long history of involvement in politics, has tacitly endorsed his campaign in an effort to pile more pressure on a government it sees as inept and corrupt.

Qadri and the military deny this.

Nevertheless, his appeal has cast fresh uncertainty over the government's effort to become the first civilian Pakistani administration to complete a full term.

The military has ruled Pakistan for over half of its 65 years since independence. Current chief General Ashfaq Kayani has vowed to keep the military out of politics.