"We have set up 'guard rails' for new projects to make the risk structure of projects transparent. Transparency of margins and risks in our order book is bigger than ever in the history of Siemens," Boersen-Zeitung quoted Thomas as saying in an interview published on Saturday.

Siemens, Europe's biggest industrial group, booked one-off charges of 900 million euros ($958 million) in its financial year through the end of September 2014 and said at the time it aimed to lower that figure to an average of 350 million euros.

"The 200 million euros that we had to shoulder in the industrial business in the full year 2015 were of course still too much," Thomas told Boersen-Zeitung.

"But project risks usually result in large sums (of charges) when they occur, so there should be a certain volatility between quarters in the future, too."

Siemens last week forecast a return to growth on all levels in 2016 after a year of upheaval in which it axed thousands of jobs at its energy division and sold its last remaining consumer businesses.

(Reporting by Maria Sheahan, editing by David Evans)