SYDNEY, Australia - Elon Musk's X has not paid a fine imposed for failing to outline its plans to stamp out content depicting child sexual abuse on the platform, Australia's internet safety watchdog told AFP on Tuesday.

Last month, eSafety commissioner Julie Inman Grant slapped an Aus$610,500 (US$388,000) fine on the company formerly known as Twitter for failing to respond to questions she sent in February, criticising the company's "empty talk" on the issue.

X was given until the end of October to pay the fine, request an extension or ask for the fine to be withdrawn. The company had requested an extension which expired last Friday.

"Twitter/X has not paid the infringement notice within the allotted timeframe and eSafety is now considering further steps," a spokesperson for Inman Grant told AFP.

X did not immediately reply to a request for comment.

Inman Grant -- herself a former Twitter employee -- last month urged X to show it was taking "tangible action" to clean up the platform.

"Twitter/X has stated publicly that tackling child sexual exploitation is the number one priority for the company, but it can't just be empty talk," she said at the time.

Billionaire Musk has slashed more than 80 percent of X's global workforce since his takeover, including many of the content moderators who are responsible for stamping out abusive content.

Proactive detection of child sexual exploitation on X fell from 90 percent to 75 percent in the three months after the takeover, Inman Grant said.

Australia has spearheaded the global drive to regulate social media platforms and it is not the first time Inman Grant has singled out X or Musk.

In June this year, she raised concerns about a spike in more general "toxicity and hate" following Musk's takeover in October last year.