Nguyen Thai Hiep, who acted suspiciously while carrying the suitcase on Chu Van An Street in Binh Thanh District on Friday, was stopped by police.
When inspecting his suitcase, authorities found 42 new iPhone 14s with original labels in foreign languages and no sub-labels in Vietnamese.
He also failed to show the necessary papers to prove their origin.
Authorities suspect him of smuggling the iPhones 14s, which were seized to aid the investigation.
Earlier, many Vietnamese flocked to Singapore and Thailand, queuing in front of Apple Stores to buy the new iPhones.
In Vietnam, iPhone 14 and iPhone 14 Plus can be ordered via some Apple's official distribution channels at the price of VND24.99 million ($1,054) and VND27.99 million, respectively, for the 128GB version.