Bangladesh's Supreme Court has reinstated a ban on Islamic political parties in the latest blow to religious hardliners in the impoverished South Asian country, a minister said Thursday.

In a detailed, 184-page verdict released late Wednesday, the Supreme Court scrapped the bulk of the 1979 fifth amendment, including provisions that had allowed religious political parties to flourish and legalised military rule.

"Secularism will again be the cornerstone of our constitution," law minister Shafiq Ahmed told AFP on Thursday.

After independence from Pakistan in 1971, Bangladesh's first constitution made secularism a key pillar.

Following a 1975 coup, the army-led government amended the constitution in 1979.

Religious parties, which were banned in the original 1971 constitution but legalised by the 1979 amendments, are now banned again, said Ahmed.

In 1988, a second military-led government made Islam the state religion in the Muslim-majority nation and incorporated Koranic verse into the constitution.

Neither of those changes are affected by the court verdict.

"But following the scrapping of the fifth amendment, these later amendments can now be challenged in court," Ahmed said.

In the verdict, which was issued in January but became trapped in an appeals process until Wednesday, the Supreme Court also declared the 1975-1990 military rule illegal, and recommended punishing military dictators, Ahmed said.

"This means that, in theory, any Bangladeshi citizen could initiate a lawsuit against a former military dictator," he said, adding that the repeal of the amendment would also limit the possibility of a future military coup.