DHAKA: Bangladesh's main Islamist party was on Thursday barred from contesting next year's elections when judges declared its charter breached the secular constitution, sparking warnings of fresh violence in the volatile nation.

Amid tight security outside the court in central Dhaka, a panel of judges approved a long-running petition that argued Jamaat-i-Islami should never have been allowed to register as a political party.

“It (Jamaat's registration) is hereby declared illegal,” said Moazzem Hossain, the senior judge hearing the case said, as he read out the brief verdict.

The country's election commission said the ruling meant Jamaat could not stand in a general election scheduled to be held in January.

A lawyer for Jamaat however said the party intended to appeal the verdict, accusing the three-judge panel of caving in to government pressure.

A lawyer for the election commission, which oversees preparations for next year's polls, said the ruling meant Jamaat could not field candidates.

“As a party, Jamaat's registration with the election commission is declared illegal, with the consequence that they cannot contest the election as a political party,” Shahdeen Malik told AFP.

“The party can still carry on with other political activities. If it amends its charter, to bring it in conformity with the constitution and reapplies for registration, it can be re-registered,” Malik added.

There were fears ahead of the ruling that it could trigger fresh protests by Jamaat supporters in a country already reeling from violence over war crimes verdicts passed on Jamaat's top leadership.

Police and members of the elite Rapid Action Battalion were deployed outside the court but there were no immediate reports of violence.

The ruling comes after groups filed the public interest litigation in January 2009 seeking to scrap Jamaat's registration.

Defence lawyer Tajul Islam said Jamaat would lodge an appeal against the verdict in the Supreme Court, the country's highest, later Thursday.

Senior Jamaat official Abdullah Taher said the party was in a state of shock, claiming the court had bowed to pressure from Prime Minister Sheikh Hasina's secular government.

“We are stunned. The ruling reflects the will of the government,” Taher told AFP.

“We'll appeal against the verdict and will also announce new political programs protesting the verdict.

“The ruling will further destabilise the country,” he added.

More than 100 people have been killed in political violence since a tribunal hearing allegations of war crimes dating back to the 1971 civil war began handing down sentences at the start of the year, including against senior Jamaat figures.

Three Jamaat defendants have so far been sentenced to death and several other party leaders are still on trial for charges including mass murder, rape and religious persecution.

Although the exact number of people killed in recent months is in dispute, Human Rights Watch said in a report Thursday that at least 150 people have died in clashes with security forces.

Jamaat says the war crimes trials are a sham aimed at eliminating the party, which is a key opposition force.

Secular protesters have long demanded that Jamaat be banned for its role in the 1971 war of independence, during which it opposed Bangladesh's breakaway from Pakistan.

About 90 per cent of Bangladesh's 153 million strong population are Muslim and the constitution was changed in 1988 making Islam the nation's state religion.

But the original constitution, drafted by the main secular party after independence, bars the use of religion in politics.

Although Jamaat has rarely won more than five per cent of votes at election time since the 1970s, it has been a member of a number of coalition governments.

It last held office in 2006 but has been in the political wilderness since its then coalition ally, the Bangladesh Nationalist Party, was beaten by Hasina's Awami League in elections two years later.