Finance Minister Yannis Stournaras told the Financial Times that Greece will work on it "as a priority."

"I first learned of (the CD's) existence from the newspapers," Stournaras said, adding that if the ministry's economic crimes unit SDOE could not track the data down "we'll ask our European partners for another copy".

Stournaras' comments came two weeks after deputy finance minister George Mavraganis told parliament that the material — apparently removed illegally by an HSBC bank employee in Switzerland — could be deemed "industrial espionage" and would therefore not be used.

Struggling to avoid bankruptcy since 2010, Greece has been trying to clamp down on perennial tax evasion and avoidance, but with limited success.

Stournaras last week said the ministry's fraud squad was investigating more than 30 cases involving the holdings and tax declarations of politicians, local council administrators and other senior public servants.

Among those under investigation whose names have been leaked to the press is parliament chief Evangelos Meimarakis, who has temporarily stepped down from his post.

The Bank of Greece was reported in July to have information on 403 Greeks who had moved at least €100,000 abroad in 2010, while claiming to have zero income.

And the finance ministry in February said Greeks had legally moved €16 billion ($21 billion) abroad in the last two years.