The eSafety commissioner has been granted a two-day legal injunction to compel X to hide posts that include graphic footage relating to the Wakeley stabbing.
X has been ordered to hide the material from all users worldwide until Wednesday at 5pm, when the matter will be considered again in more detail.
The eSafety commissioner last week ordered X, formerly known as Twitter, and Meta, which owns Facebook and Instagram, to take down the Wakeley-related material.
Meta did so, but X objected, accusing the commissioner of overstepping her legal powers. The platform had threatened legal action, but said it would comply in the interim.
But now the eSafety commissioner has taken the matter to court, arguing X has failed to comply with the law because its interim action was to "geoblock" the content, not delete it.
Geoblocking means the content cannot be viewed in Australia, but this can be circumvented by anyone using a virtual private network (VPN), which obscures a user's location.
Lawyers for the eSafety Commission told the federal court geoblocking was not enough to comply with the Online Safety Act.
That law empowers the eSafety commissioner to order the removal of material that "promotes, incites, instructs in or depicts abhorrent violent conduct, such as kidnapping, rape, torture, murder, attempted murder and terrorist acts", if it could "go viral and cause significant harm to the Australian community".
Marcus Hoyne, a lawyer appearing on behalf of X, sought to delay the court's decision on an injunction, saying he had not been able to seek instructions from his client.
"We're just not in a position to respond to it [the application] at this time," he said.
The judge granted a temporary injunction for two days, giving X time to respond but siding with the eSafety commissioner in the meantime.
It means that, within 24 hours, X must hide the posts in question from all users worldwide, in the form of a warning notice covering the posts, which users cannot remove.
X will then have the opportunity to argue against the injunction request on Wednesday before a final decision is made.
A spokesperson for the eSafety Commissioner said companies like Google, Microsoft, Snap and Tiktok worked with the office to remove the material.
"Some of these companies have taken additional, proactive steps to reduce further spread of the material. We thank them for those efforts," the spokesperson said.
"However, eSafety determined last Tuesday that Meta and X Corp were not taking adequate steps to protect Australians from this material. Consequently, eSafety issued Class 1 notices to both companies, formally seeking removal of this material from their platforms.
"In the case of X Corp, eSafety was not satisfied the actions it took constituted compliance and sought this injunction from the federal court."
On Sunday, a spokesperson for X had said the posts in question "did not violate X's rules on violent speech" and argued the order was "not within the scope of Australian law".
The platform argued the government could not order it to delete a post worldwide.
"The eSafety commissioner does not have the authority to dictate what content X's users can see globally. We will robustly challenge this unlawful and dangerous approach in court," a company spokesperson said.
X owner Elon Musk accused the government of "censorship" for seeking what he called "global content bans".
But lawyers for eSafety argued the commissioner did have legal authority to make orders about the global status of posts since VPNs meant that anything available globally could be accessed in Australia.
Prime Minister Anthony Albanese on Monday affirmed his full support for the eSafety commissioner and his expectation that X comply.
"This isn't about freedom of expression … Social media has a social responsibility," he said.