Johnson, the former star of 80s police show Miami Vice, told CNN's Live With Larry King the documents detailing �5bn worth of funds in other people's names were from potential film investors.

He told the show the suggestions of money laundering in a German newspaper had had a terrible effect on him.

"My son called me crying. It's been terrible. It's been terrible. This has been one of the most difficult weeks of my life."

The documents were found when Johnson's car was stopped in a routine check by German customs officials last November.

Johnson told Larry King the newspaper reports had "perpetuated this story of money laundering based on no evidence, based on no investigation".

He said he was considering suing the paper and other German media that had reported the story.

Johnson said he had thought nothing of the search until the allegations were made.

Investigating documents

He said he "signed some autographs, we joked around" of his time with the customs officials.

German authorities said on Wednesday they were investigating documents, reportedly detailing transactions worth �5bn, which were found in his car during a routine check at a Swiss border crossing.

But customs spokesman Wolfgang Schmitz said it was not a criminal investigation and there had been no indication of any wrong-doing.

Johnson said last week his reputation had been damaged already by the affair. Two of his bank accounts had been closed.

But Johnson added: "I don't know that I will ever be able to clear my reputation and regain my credibility.