(Adds ECB denial)
BERLIN/BRUSSELS, March 4 (Reuters) - Two German newspapers said on Monday there were growing doubts within the European Central Bank (ECB) about its continued participation in the so-called "troika" of the European Union, International Monetary Fund and the ECB.
The ECB denied as unfounded the advance excerpts of articles to appear on Tuesday in the two German newspapers, die Welt and Sueddeutsche Zeitung.
The conservative Die Welt and liberal Sueddeutsche Zeitung said some ECB members were concerned that participation in euro zone rescue efforts could create a conflict of interest for the ECB and compromise its independence.
"The level of discomfort has reached such a level that there are considerations among some important members of the ECB to leave the troika entirely," Die Welt reported, citing a financial source it did not identify.
It quoted a government source in Berlin as saying there were two reasons for the concerns. It had become quite normal for the ECB to take part in rescue efforts for struggling euro zone countries.
Secondly, Die Welt said, the ECB's political influence was growing. Together with the IMF and the EU, it was imposing gigantic adjustment and reform programmes on ECB nations.
"The ECB will not withdraw from the troika and any reports, which suggest this are unfounded. We don't see any threat to our independence while we are participating in the troika," ECB board member Joerg Asmussen told reporters in Brussels.
"The ECB participation in the troika is key. We have great knowledge about Europe, its institutions, its economy and we especially provide expertise on macroeconomic and especially financial sector issues. We will not withdraw from the troika."
Asked about the reports, Olli Rehn, the EU Economic and Monetary Affairs commissioner, told reporters in Brussels the EU was working closely together with the ECB and IMF.
"I do not have any clue what you're talking about and we work very constructively with (ECB) President (Mario) Draghi and the other troika partners," Rehn said.
Die Welt said not everyone in the ECB had the same concerns.
The Sueddeutsche Zeitung quoted one ECB source as saying: "The problem is there. But we only have an advisory role in the troika and not a deciding role. The programmes are signed by the Commission and the IMF." (Reporting by Erik Kirschbaum and Annika Breidthardt; Editing by Andrew Roche and Jon Hemming)