Uber is facing a criminal investigation in the US over its use of software to prevent authorities carrying out stings and legal checks.

Uber has acknowledged its use of the software, known as "Greyball", to identify and avoid government officials trying to clamp down on its operations in areas it was not yet licenced

The US Department of Justice has opened an investigation into Uber, although the nature and consequences of the probe remain unclear.

Uber has used the software to avoid authorities in the US, France, Australia, China and South Korea.

It is claimed Uber used the software to trick authorities into thinking they were using the app when in fact they were using a modified version.

This modified version showed them fake "ghost vehicles", allowing them to hail a car that would be cancelled a couple of minutes before arriving at the pickup point.

In a statement to The New York Times, Uber said that the software is designed to block "users who are violating our terms of service" and "officials on secret 'stings' meant to entrap drivers".

How Uber gained the information about users who might be involved with the authorities is unknown.

The DoJ has so far declined to comment on the case.