Germany's finance ministry on Saturday urged German media to hand over information on suspected tax evaders to authorities, after revelations of widespread German involvement in offshore tax structures.
Focus magazine reported it had information on 100,000 individuals in Germany to have used tax havens and 260 million financial transactions to and from such zones.
Media have declined to hand over the data.
"Tax authorities and prosecutors must examine what conclusions and clues can be drawn from the information already published," a finance ministry spokesman said on Saturday, adding the ministry welcomed media efforts to investigate tax evasion, considering these supportive of its own efforts.
Finance Minister Wolfgang Schaeuble has said Berlin intends to push for greater international cooperation in fighting tax evasion. Economy Minister Philipp Roesler also urged the press to hand data to authorities.