An investigation is underway after a male police officer allegedly threatened to kill his lover.

A police spokesperson confirmed that the investigation was being conducted by the Family and Child Protection Department. No further details were provided.

In an audio clip circulating on social media, a man can be heard using foul language and issuing death threats.

The woman who faced the threats said in a Facebook post that she was in mental fear and accused the man of deadly attacks previously.

"I am facing a mental fear today. I have been attacked by this man before. I don't know how many years it will take me to recover," she said.

Police did not identify the officer who allegedly threatened the woman.