The sacked chief justice of Pakistan, Said-uz-Zaman Siddiqui, has defended his decision not to sign a new oath of allegiance to the country's military rulers.

He said what the judges had been asked to do was not in accordance with Pakistan's constitution.

"I am on record that I will work under the constitution, not under the provisional constitution," he said.

Mr Siddiqui and five senior judges were replaced after refusing to sign an oath of allegiance to a provisional constitution which bars the higher courts from ruling against military leader General Musharraf and his officials.

A new chief justice, Irshad Hassan Khan, has now been appointed to the Supreme Court.

Condemnation

Mr Siddiqui said his decision was a matter of individual choice, which was taken regardless of the fact that 85 out of 100 judges had taken the new oath.

Justice Siddiqui had been due to hear a case next week contesting the legitimacy of the military take over last year.

Lawyers and human rights activists have condemned the move.

The deputy head of the Pakistan Bar Council, Sheikh Naeem Goreja, said the move had "degraded" the judiciary.

Human rights lawyer and UN rapporteur Asma Jehangir said it raised questions about the independence of the judiciary.

"I salute those judges who have refused to take the oath," she said.

The dismissals of the judges came as the much delayed trial of the ousted Prime Minister, Nawaz Sharif, finally got under way.

The new judges were sworn in to their positions by Pakistan's President Rafiq Tarar, in the presence of the country's military ruler, General Pervez Musharraf.

"Whatever has happened is in the interests of the country," General Musharraf said after the ceremony.

Allegiance

Soon after taking over in a military coup, General Musharraf suspended the constitution and put in place a provisional constitutional order.

The order suspended parliament and provided emergency constitutional backing to the new military rulers.

In a move to consolidate their hold over the judiciary, all judges were directed to swear a fresh oath.

The BBC's Zaffar Abbas in Islamabad says the move by the judges comes as a major embarrassment to the military administration.

General Musharraf's action against the judges echoes a similar step by Pakistan's last military ruler, General Zia ul-Haq, who put in place judges loyal to his regime.