LONDON, Sept 27 (Reuters) - Standard Chartered STAN.L has referred allegations of impropriety at an Indonesian company that the bank's private equity arm invested in to the appropriate authorities, the bank said on Tuesday.

The Wall Street Journal earlier reported the bank faced an investigation by the U.S. Department of Justice as to whether StanChart failed to stop alleged misconduct at Maxpower Group Pte Ltd, a power plant builder.

"Standard Chartered takes very seriously allegations of impropriety in any of our private equity investments. We proactively referred this matter to the appropriate authorities and have conducted our own review," a spokesman for the bank said in an emailed statement.

(Reporting by Lawrence White; editing by Susan Thomas) ((lawrence.white@thomsonreuters.com; +44 207 542 6137; Reuters Messaging: lawrence.white.thomsonreuters@reuters.net))