The advocacy group Missing Children Europe said it welcomed the EU’s call for “viable and effective, non-custodial measures”.
It said it would monitor the EU on the issue to “make sure that these commitments do not remain words on paper”.
Around 12 per cent of global migrants, or 33 million, were estimated to be children in 2019.
The UN’s International Organisation for Migration previously said that children in Europe sometimes slipped under the radar and avoided accessing health or education services in order to evade detection.
In addition to avoiding immigration authorities, children sometimes went to ground because of pressure to send money home or to repay debts incurred on their journey to Europe, the IOM said.
Migrant children struggling to support themselves could become “dependent on work performed in informal and dangerous settings”, it said.
Others were prone to leaving refugee shelters because of poor living conditions and their inability to access education.