The official needed a police escort after the Mothers of the Plaza de Mayo group and its supporters blocked access to its offices in Buenos Aires.
"They gave the order to break the gate. They've no respect for anything, they're smashing up the country," said Hebe de Bonafini, the 90-year-old founder of the movement.
The group, which celebrated the 40th anniversary of their first meeting on Sunday, has never let up in its quest to discover the truth behind the disappearance of their children during the 1976-83 dictatorship.
They were declared bankrupt in June 2017 as a result of a claim for unpaid wages by a former employee.
De Bonafini said the judicial order to enter the group's premises was retaliation for its opposition to President Mauricio Macri.
"This is the price for having said from the first day that he's our enemy, we certainly didn't get that wrong," she said.
De Bonafini and the group's former president Sergio Schoklender have been accused of diverting public funds.
Authorities suspect the pair of committing irregularities when the association built social housing from 2005-11, during the presidencies of Nestor and Cristina Kirchner.
Nestor Kirchner, who died in 2010, was president from 2003-2007 before he was succeeded by his wife Cristina for two terms until 2015. She is Macri's closest rival ahead of presidential elections in October.
On April 30, 1977, 14 women, mostly housewives, rallied in front of the presidential palace, which had been occupied just over a year earlier by the military.
The military mockingly branded them "las locas" (the madwomen), but the women have continued to meet every Thursday at 3:30 pm (1830 GMT) ever since, despite the youngest of them now being in their 80s.
Some 30,000 opponents of the dictatorship were disappeared during military rule from 1976-83.