Fong Poh Huat, who used his passport as collateral for a gambling loan received a three-month jail sentence on Nov 30.
The Immigration and Checkpoints Authority (ICA) reported that Fong, 38, was charged with making two false statements to the ICA and the Consulate-General of Singapore in Ho Chi Minh City, Vietnam.
In February this year he had travelled up to Vietnam seeking business opportunities as well as to look for his estranged wife.
During his time there he had visited the casino to gamble and lost about $10,000.
In an attempt to recoup his losses he borrowed US$12,000 (S$15,380) from another gambler and lost that as well.
The man, known only as 'Johnny' then asked him to sign a 'Personal loan agreement form' that required him to pay back the loan in 10 days with an additional US$4,500 as interest.
He also had to pass 'Johnny' his passport as collateral.
Unable to raise the money in time, he went to the Consulate-General in Ho Chi Minh City to ask for a Document of Identity (DOI), an emergency travel document to return to Singapore, claiming that he had dropped his passport.
Upon his return, he was advised by the ICA to apply for a new passport, which he did but claimed this time that it was stolen by a motorbike rider.
However, ICA spotted the inconsistencies and he was charged on June 17 this year.
He could have been fined up to $10,000 or jailed up to 10 years or both.
The ICA also said that it reserves the right to deny issuing passports to anyone who misuses the document.