Prime Minister Malcolm Turnbull's son, Alex Turnbull, has been one of the few, if only, former Goldman Sachs bankers to raise concerns publicly about the investment bank's involvement in what could be one of history's great frauds.

Now, Turnbull's warnings seem prescient. Goldman Sachs' one-time partner and south-east Asia chairman, Tim Leissner, is discussing pleading guilty to criminal charges stemming from an alleged scheme to steal billions from a Malaysian state investment fund known as 1MDB, the Wall Street Journal reported.