The move is in response to a report on the day of the judgment last week in which The Times predicted the ruling.
The Tory former Chancellor of the Exchequer Lord Lamont of Lerwick - a staunch supporter of General Pinochet - had urged the Lord Chancellor to mount an inquiry into the report.
Last night, in a written parliamentary answer, Lord Irvine of Lairg said: "... the Clerk to the Parliaments has instituted a leak inquiry into this matter in order to determine, first, whether there was any improper disclosure of the law lords' opinions, and, second, if improper disclosure is found, its origin."
In response to another question from Lord Lamont, Lord Irvine said: "It is not in the interests of justice for the deliberations of judges to be leaked to the newspapers in advance of delivery of a judgment."
The Times, in an article by its legal correspondent, Frances Gibb, reported on the day of the judgment that the law lords would rule 5 to 2 in favour of lifting General Pinochet's immunity from prosecution for crimes committed after 1988. In the event, the law lords reached that decision, by a majority of 6 to 1, with minor differences between some of the judgments.
Lord Lamont welcomed the decision to set up a leak inquiry. "This is yet another aspect of this case where the whole British legal system has fallen down," he said.
"It seems to me that the conclusions of the law lords were pretty widely known."Reuse content