Thousands of Wonga customers are being alerted about a potential data breach that may have resulted in hackers stealing personal and financial data from the firm. Wonga confirmed that customers' data may have been accessed by hackers and that it was "urgently investigating" the matter.

The alleged data breach is believed to have potentially affected 145,000 customers in the UK and another 25,000 in Poland, according to reports. Wonga is yet to disclose details of the alleged breach, including how, when and where it occurred.

The online lender claimed that it is "still working to establish the full details" of the incident. However, it is believed that the data likely stolen by hackers could include customers' names, e-mail addresses, home addresses and phone numbers. The company also warned that the last four digits of customers' card number, as well as bank account details and sort code could have been accessed by hackers.

The company said in a statement: "We do not believe your Wonga account password was compromised and believe your account should be secure, however if you are concerned you should change your account password. We also recommend that you look out for any unusual activity across any bank accounts and online portals."

Reports speculate that the alleged data breach will likely hit the firm hard and may impede Wonga's recent strides in re-establishing its reputation. Financial regulators had previously reportedly found that the company granted loans to customers who couldn't afford to repay and even issued letters from fake law firms to chase bad debts. The company has since undergone an executive shakeup and now has new directors and short-term payday loans.

Following news of the Wonga breach breaking out, a spokeswoman for the Information Commissioner's Office said: "All organisations have a responsibility to keep customers' personal information secure," the BBC reported. "Where we find this has not happened, we can investigate and may take enforcement action."