Herve Falciani, the former HSBC employee who supplied information on the bank's clients and their tax situation, said he was willing to return to Switzerland to stand trial if he was given assurances that he would not face immediate arrest.
Geneva's public prosecutor earlier on Wednesday searched HSBC's lakeside Swiss office after opening a criminal inquiry into allegations of aggravated money laundering, which emerged in 2008 after Falciani fled with files he took from the bank.
"I hope to have the possibility of a right of safe passage first to attend my trial, I am not trying to dodge my responsibility," Falciani told Swiss French-language broadcaster RSR, which said he was speaking from a cafe in Italy.
Under Swiss criminal law, prosecutors may grant a so-called "safe conduct" preventing its subject from facing arrest.