By Ray Furlong
BBC News, Berlin
Ex-German leader Gerhard Schroeder has rejected criticism linked to his new job as head of a company he launched with Russian President Vladimir Putin.
Mr Schroeder (right) and Mr Putin helped launch the firm last year
The company, set up last year, is jointly owned by Russia's state-owned gas giant, Gazprom.
Mr Schroeder said he would be taking legal action after opposition politicians accused him of sleaze.
The new chancellor, Angela Merkel, has called for debate on a code of conduct for politicians entering business.
'Conflict of interest'
In remarks made to the Suddeutsche Zeitung newspaper, Mr Schroeder says the allegations against him are "nonsense" and announces that he is taking legal action - although he does not give any details about this.
Mr Schroeder and President Putin signed the deal to build the gas pipeline underneath the Baltic Sea 10 days before the general election in September - earlier than originally planned.
Politicians and the media have suggested there was a conflict of interest, with Mr Schroeder allegedly feathering his nest while acting in a public capacity.
"Schroeder ruins his reputation" was one front-page headline on Tuesday.
But Mr Schroeder said he was only offered the job on Friday last week, the same day that his appointment was announced.