Greece's finance ministry asked a prosecutor to launch an investigation into debt restructuring rumors that helped drag Greek stocks down on Wednesday.

Greek bank stocks fell 4.58 percent on Wednesday and the broader Athens bourse index lost 2.62 percent, underperforming pan-European indices on what traders said where rumors, spread by email, that the country would soon restructure its debt.

The Greek government has repeatedly said it would not restructure the country's debt, in defiance of market sentiment that such action was increasingly likely.

"The ministry urgently requested the prosecutor's office to launch a criminal investigation regarding the move in the Athens Stock Exchange and the bond market," the ministry said in a statement.

"An email originated from the traders of an international investment bank was forwarded to the prosecutor's office. Such rumors are obviously ridiculous," it said.

Greek bank shares have lost 16 percent so far this year after losing 53 percent in 2010.