DHAKA (AFP) - Bangladesh authorities on Monday (Nov 12) announced they were delaying next month's general election by a week following an appeal from the country's opposition alliance, an official said.

"The vote will now be held on Dec 30," Election Commission spokesman S.M Asaduzzaman told AFP.

The Bangladesh Nationalist Party (BNP) had protested the Dec 23 election date announced last week, saying more time was needed to prepare for the poll.

The BNP - whose leader Khaleda Zia is behind bars - had asked for an extra month to campaign against Prime Minister Sheikh Hasina.

The prime minister, who is running for a third consecutive term in office, has been accused of cracking down on her opponents ahead of the poll, with thousands of BNP activists detained in recent months.

A party spokesman warned the opposition could reconsider its decision to contest the election if an even playing field was not assured.

"Our activists are still being arrested," BNP spokesman Fakhrul Islam Alamgir said in Dhaka.

"We have said we would definitely rethink our decision if this doesn't stop and an environment is not created for a vote."

The BNP boycotted the 2014 election over fears it would be rigged, allowing Hasina to walk into a second term unchallenged.

Veteran opposition leader Khaleda Zia remains behind bars serving a decade-long jail term for corruption charges her supporters say were politically motivated.

Zia, 73, has virtually no time to appeal her sentence and will almost certainly be banned from contesting the election against her arch-rival Hasina.

The opposition also says some 5,000 of its activists have been detained in a recent crackdown, depriving it of a grassroots presence vital to fight any polls.

The arrest of activists and prominent dissidents including student leaders and a top photographer have also cast a shadow over the buildup to the vote.

The opposition has said the charges against Zia, a two-time former prime minister, and other party activists, were deliberately planned by the ruling party.

Early this month, Hasina rejected a request from the BNP and its allies to dissolve Parliament and let a neutral caretaker government organise the election. It had also asked for Zia to be released so she could run.