Sekdah Somon and Buxoo Nabilah Bibi face more than 300 charges, including human trafficking, over their alleged role in bringing 101 men to Vanuatu.
The Vanuatu High Court on Tuesday heard the defendants' application for bail, which argued they needed to be released to pay their families' debts.
The Vanuatu Daily Post reports that Chief Justice Vincent Lunabek ruled against the application.
During the hearing, public prosecutor Josiah Naigulevu said the defendants were also wanted by authorities in Mauritius.
The Bangladeshi men are said by their lawyers to be in legal limbo as key witnesses in the High Court case in the capital Port Vila, where the Vanuatu government is providing food and housing for the men.
A representative for the migrants has told RNZ Pacific they don't want to return to Bangladesh because they fear they will be killed over outstanding debts there.