* Board has "full confidence" in CEO Bjerke - chairwoman
* Norwegian government to examine DNB's findings
* DNB says investigating processes at Luxembourg arm (Adds detail)
OSLO, April 11 (Reuters) - The board and top managers at Norway's largest bank didn't know its Luxembourg arm had helped some customers set up offshore firms, it said on Monday, announcing the results of an internal investigation into revelations in the "Panama Papers" leaks.
After the leaks were published, DNB said on April 4 it had helped about 40 customers set up offshore companies in the Seychelles between 2006 and 2010 and regretted doing so.
"Let me make it perfectly clear. I had no knowledge about this, but what has happened in this period is my responsibility," Chief Executive Rune Bjerke told a news conference.
The Panama Papers, reported by a group of media organisations, show the extent to which the world's wealthy have been able to use offshore firms to reduce their tax bills.
Banks mentioned in the leaks from law firm Mossack Fonseca have come under pressure from the media, regulators and politicians to explain their actions.
DNB chairwoman Anne Carine Tanum said the board had "full confidence" in Bjerke and the results of the investigation did not give grounds to question his position.
The Norwegian government said in a separate statement it would examine DNB's findings. The state is DNB's top shareholder with a 34 percent and had demanded it explained its actions in helping customers set up offshore firms.
Bjerke told Reuters on the sidelines of the news conference that the correct processes had not been carried out at its Luxembourg business and it would investigate further. (Reporting by Camilla Knudsen; Writing by Terje Solsvik and Gwladys Fouche; Editing by Greg Mahlich and Mark Potter)