A federal judge in Virginia temporarily blocked the Trump administration from transferring any money into a secretive and loosely controlled $1.8bn fund while a legal challenge proceeds.

The order from US district judge Leonie Brinkema on Friday bars the government from “taking other further action” in the creation or operation of the fund while legal arguments in a case challenging the fund continue. The order is intended “to ensure no funds are irreversibly disbursed from the Anti-Weaponization Fund”, Brinkema wrote.

The Trump administration announced it was creating the $1.776bn fund last week in order to resolve a $10bn lawsuit filed by Donald Trump and his sons over the leak of Trump’s tax returns. The government did not take preliminary steps to try to defend itself in the lawsuit, prompting accusations of improper collusion and corruption.

The government has said that anyone who is a victim of government weaponization can submit a claim to the fund, which will be controlled by four commissioners appointed by the US attorney general and a fifth appointed in consultation with congressional leadership. All the commissioners can be fired by Trump for any reason.

There are no restrictions on who can apply for money from the fund, and even Republicans have expressed outrage that January 6 rioters who assaulted police officers could receive a payout. The fund also does not have to disclose how much it paid to whom and its reasons for doing so, prompting criticism that it is essentially a slush fund.

The ruling from Brinkema, a Bill Clinton appointee, came in a lawsuit filed by the watchdog group Democracy Forward seeking to block the fund. The ruling is intended to preserve the status quo and was necessary after the government declined to provide assurances that no funds would be transferred or paid before 19 June to allow for adequate briefing in the case.

“We are pleased that the court granted our request to ensure the administration does not distribute taxpayer funds until our motion has been considered. The court acted quickly to stop this unlawful scheme before money could start flowing out the door,” the plaintiffs said in a statement.

“The Department remains extremely confident in the legality of the Anti-Weaponization Fund which is supported by ample precedent, including Obama-era settlements. We will not allow the policy preferences of judges to interfere with our efforts to provide restitution to victims of lawfare,” a justice department spokesperson said in a statement.

Money from the fund will come from the judgment fund, a perpetual appropriation the government can use to settle cases. Critics of the agreement have said using the judgment fund effectively allows Trump to do an end-run around Congress’s appropriation power.

It is an open legal question whether there is any plaintiff who will have suffered sufficient injury to challenge the creation of the fund. The Democracy Forward suit was filed on behalf of a former federal prosecutor who led a taskforce prosecuting January 6 protesters, a California professor acquitted of charges attacking immigration agents, the Connecticut city of New Haven, as well as the watchdog group Common Cause and the National Abortion Federation.

Police officers who defended the Capitol on January 6 have also filed a separate lawsuit in the District of Columbia challenging the fund.