The eight were arrested this week for a second time after being taken into custody in December as they were trying to leave the southern African country with four children.
The group of four couples say they legally adopted the children from neighboring Democratic Republic of Congo but have been accused by Zambian authorities of trafficking the minors.
They have been jointly charged with a senior Zambian immigration official.
On Friday they appeared before a magistrate in the northern city of Ndola, 300 kilometers north of the capital Lusaka, near the DRC border- and applied for bail.
"Their passports are with the immigration department," their lawyer, Kelvin Silwimba, told the court.
But prosecutors opposed the bail application arguing the eight are at flight risks.
Magistrate Jennipher Bwalya adjourned the case with the eight to remain in custody pending a decision expected early next week.
The group had been set to leave the country this week after the same court ordered their release.
But they were arrested again at an airport as they prepared to depart.
The case has sparked a fierce public debate in Croatia and put international adoption in the spotlight in the Balkan nation, where potential adopters vastly outnumber eligible children.
