A major finance firm says its recent hack went deeper than first thought. 

Non-bank lender, Latitude Financial, has confirmed that the recent cyber attack on its systems was far more extensive than originally thought, with approximately eight million people's data believed to be stolen. 

The company initially announced on March 16 that it believed around 330,000 people's data had been accessed. 

In an update to the Australian Securities Exchange (ASX), Latitude disclosed that approximately 40 per cent of the 7.9 million driver's licence numbers that were stolen, or 3.2 million, were provided to the company over the past decade. 

The stolen data includes current and former customers of Latitude Financial. 

Latitude Financial has yet to disclose exactly how many customers have been impacted by the breach. 

The stolen data includes customers' names, dates of birth, address, and telephone numbers. 

The company has promised to reimburse customers who choose to replace their stolen identification documents. 

Cybersecurity experts have told reporters that it is “pretty unbelievable” that Latitude Financial kept historical customer data on file dating back to 2005, when it was still owned by GE Capital.