Australia's most lucrative gold mine is out of action indefinitely after a "large seismic event" damaged parts of Newcrest's Cadia operation and put a cloud over the company's ability to meet its full-year gold production target.

The seismic event rocked the mine early on April 14 and while none of the workers were killed nor injured, the event has been deemed serious enough for New South Wales safety regulators to issue a "prohibition notice" over the mine.