Twenty-four caskets containing the only bodies recovered from the Mediterranean's worst migrant disaster have been laid out for a memorial service in Malta for the estimated 800 victims.

Malta's president and prime minister, Italy's interior minister and the EU's migration commissioner were on hand for Thursday's service, which includes Christian and Muslim prayers.

Flowers lined the route that the caskets took from Malta's morgue to the service on a helipad of the island nation's main hospital.

Only 28 people survived the capsizing of the migrant boat last weekend. The suspected captain and a crew member of the smuggler boat have their first court hearing Friday.