The Department of Foreign Affairs believes the Irish passport carried by the man arrested carrying drugs in his stomach in Brazil is genuine.
However checks are being carried out by the Department to verify whether the man is the legitimate holder of the passport.
The Brazilian police had released a colour x-ray of the man's stomach showing a large number of bags of cocaine in his stomach.
Police in Sao Paulo's Congonhas airport were alerted after noticing the man's nervous behaviour.
They estimated the drugs would have been worth up to €150,000.