Hundreds of families have had their child benefit payments stopped because they returned to Northern Ireland via Dublin airport.
It follows the introduction of a new government anti-fraud system designed to track those who leave the country but do not come back after eight weeks, raising a red flag at HMRC for possible emigration.
Sinn Féin MP Dáire Hughes, who is representing 14 of the families affected, called the system "flawed".
As first reported in The Detail, HMRC have apologised for the mistake and said they were "working at pace" to reinstate claims so families are "not left out of pocket".

