In a statement, Bishop William Nolan and Bishop Paul McAleenan said: "Their presence is discouraged by the authorities; police tactics include interrupting sleep and confiscating tents and sleeping bags."
They want unaccompanied minors' rights as children to be recognised by both French and UK authorities.
"Aid agencies report that the policies of the British government have resulted in young people turning to people smugglers in attempts to reach the UK.
"We ask both UK and French governments to develop infrastructures to enable dignified living in Calais."
They also raised concern that families have been split-up and ask for children to be reunited with their parents.
Bishop William and Bishop Paul added: "As the season of Advent begins, we are reminded again that the Holy Family were themselves refugees forced to flee their home seeking sanctuary in a foreign land."
