Fraudsters are targeting vulnerable, low-income groups, including students, people on benefits and new entrants to the UK, with job adverts that recruit people to money launder thousands of pounds for criminal gangs abroad.

The fake job offers, which appear online or are sent in unsolicited emails, are for roles such as "money transfer agent" or "payment processing agent", and turn applicants into "money mules", according to Financial Fraud Action UK (FFAUK).

People who apply are offered a job and asked to receive money into their bank account and transfer it to another account, retaining a cut for themselves as their pay.

But the money being transferred is stolen, often as a result of fraud on another bank account, and is then laundered to overseas banks. Mule fraud is a criminal activity and carries serious penalties for anyone who gets involved.

Criminals looking to recruit a money mule target vulnerable people on low incomes who are tempted by the lure of an apparently easy way of making extra cash. Figures from research by ICM, in partnership with FFAUK, show the fake job offers have been received by around 15% of adults in the UK.

Of those who have received such a job offer, ICM said a fifth (21%) admitted they considered accepting the work, and 6% went on to volunteer to become a money mule.

The Bank Safe Online website, run by the UK Payments Council has published some examples of adverts that have been used by fraudsters to lure unwitting money mules.

One, from Impex Consult Financial Consulting Group, reads: "We offer you to start your career in our team as a Transactions Specialist. The duties would involve prompt processing of incoming cash funds and their transfer to accounts indicated by our managers. With efficient time management, your whole day's work should take three to five hours."

When caught, mules can suffer severe penalties, including a prison sentence of up to 10 years. Any profits they have made will be recovered from their accounts to reimburse the victims of fraud, while their bank account will be closed down and a bank may even share details of the activity with other banks (meaning they may no longer be able to open a bank account in the UK).

DCI Dave Carter, head of the dedicated cheque and plastic crime unit, said: "What might initially seem an attractive method of boosting your income during tough times is in reality the work of determined international criminals, aiming to turn the public into an unwitting army of accomplices to fraud.

"These new figures demonstrate the gap between perceptions of the public and the real seriousness and criminality of this conduct. Whether through naivety or 'willful blindness' to the consequences, members of the public need to reject any approach for their bank account to be used in this way."

In July 2012, the Guardian reported on the case of a 16-year-old student who had been turned into an unwitting money mule, helping fraudsters to launder around £5,000. The teenager was lucky – his bank forcibly closed his account but did not pursue the matter further with the police.