Sleman Ahmed, 33, was detained in Bordesley Green in Birmingham, and Shamel Zorab, 37, in Eccles in Greater Manchester.
The Iraqi nationals are wanted by authorities in Belgium and are due in court on Friday.
They are accused of being in contact with a web of people-smugglers and collecting fees from migrants.
The National Crime Agency (NCA) and Belgian Federal Police are investigating a Kurdish criminal network suspected of smuggling people into the UK in lorries.
Ten people have already been arrested in Belgium and await trial there.
The arrests were part of an operation co-ordinated by the NCA and supported by officers from Greater Manchester Police and West Midlands Police.
Colin Williams from the NCA said: "We believe this crime group is involved in attempting to smuggle people into the UK on an almost daily basis, and our co-operation with the Belgian authorities on this investigation continues."
Mr Ahmed and Mr Zorab are due at Westminster Magistrates Court for an extradition hearing on Friday.
Two men have been arrested on suspicion of being part of a network which daily smuggled up to 20 migrants into the UK.