The two Chinese men, Si Long, 28, and Yuan Deng Hui, 27, both found guilty of "providing loans in civil transactions at unreasonably high interest rates," were sentenced to a year and six months in jail each.

The three Vietnamese accomplices – two men and a woman, were sentenced to one year in jail each.

The loan racket was busted last April with the police arresting the five defendants following reports from people who were being threatened over delayed repayment of the loans.

Jiang Miao and Niu Li Li, both Chinese nationals, were identified as the ringleaders who hired Long and Hui to set up financial companies in Ho Chi Minh City's Binh Tan District in April last year. They also created three apps – vaytocdo, Moreloan, and VDonline, offering loans of over VND100 billion (around $4.26 million) at 2.5 percent interest per day, equivalent to 75 percent a month and 912.5 percent a year, more than 30 times higher than rates at local commercial banks.

Long and Hui advertised the three loan apps on social media like Facebook and via leaflets distributed on the street, offering people fast and easy loans with little paperwork.

The duo employed nearly 40 customer service staff who instructed borrowers on downloading the company's apps on their phones. Customers had to provide personal information including ID card information and bank account numbers; and agree to seven mandatory terms which allow the app to access phone directories.

Their goal was to get the phone numbers of the borrower's relatives, colleagues and friends who could be intimidated later for debt collection.

Investigators said the ring had nearly 500 customers and had earned profits of over VND658 million ($28,300) after six months of operation.

Long and Hui ran the financial companies with a monthly salary of VND35 million each, while three Vietnamese accomplices were hired to work as interpreter, accountant and HR manager to assist the two Chinese operating the ring.

Police haven't caught Miao and Li yet since they were managing the ring via phone and the internet.

Investigators in Vietnam have said around 210 loan-shark rings are operated by more than 2,000 people across the country, targeting low-income workers in urgent need of money. The borrowers approach the loan sharks because they cannot afford the time and paperwork demanded by banks.