A Bangladesh court has handed death sentences to seven members of an Islamist militant group for plotting an attack on a cafe in 2016 that killed 22 people, mostly foreigners, in the south Asian nation's worst terror incident.

"Charges against them were proved beyond any doubt. The court gave them the highest punishment," public prosecutor Golam Sarwar Khan told reporters after the verdict in the capital, Dhaka, amid tight security.

One of the eight people accused was acquitted, he added.

After the ruling, the accused men in the dock in a packed courtroom looked defiant and shouted, Allahu Akbar (God is Greatest), witnesses said.

The July 1 attack on the restaurant popular with foreigners in Dhaka's diplomatic area shocked the nation of 160 million and signalled a chilling threat to business, including the vital garment exports sector.

Five militants stormed the Holey Artisan cafe, took diners hostage and killed them over 12 hours. Nine Italians, seven Japanese, an American and an Indian were among the dead. The attackers were killed in a rescue bid by army commandos.

Khan said the seven men convicted today were involved in planning the attack. They belong to the group, Jamaat-ul-Mujahideen Bangladesh, that seeks to establish Syariah rule in the predominantly Muslim country. 

-- Reuters