The Republic of Ireland and Belgium are the new frontiers in the battle against illegal immigration into the UK, the National Crime Agency (NCA) has said.
People smugglers are increasingly opting for the two countries because security elsewhere has become effective.
Investigators said Ireland has become an attractive option because illegal immigrants are able to take advantage of the “soft” border with Northern Ireland and then make their way to the British mainland.
Tom Dowdall, deputy director of the NCA said the people traffickers were seeking to exploit the border arrangements between Northern Ireland the Republic.
He said: “The level of border controls, or requirements of border controls, are different to that from others travelling on from other countries.
“We have seen some evidence of that being abused.
“Migrants are smuggled by organised crime groups into the Republic of Ireland sometimes by air, from Eastern Europe and Asia.
“Sometimes it will be by the sea through the Irish sea ports, then flying in to the UK.
“Migrants move across the land border from the Republic of Ireland and Northern Ireland and then cross the border from there.
“That border is not an internal border, its internal travel that takes place.”