A man with €91,000 cash was stopped by Revenue's Customs Service at Rosslare Europort on Saturday.
The Swedish man in his 40s was stopped when he was about to board a ferry to France.
The seizure was a result of routine risk profiling.
Judge Donnacha Ó Buachalla in Wexford District Court granted a three-month detention order to carry out further investigations.
This is the third cash seizure made by customs officers at Rosslare this year.
To date this year Revenue's Customs Service has made 31 cash seizures totalling €1.1m.