Thousands of people protested in Budapest near parliament on Tuesday demanding the chief prosecutor and Prime Minister Viktor Orban resign after a former government insider accused a senior aide to Orban of trying interfere in a graft case.
Protesters marched from the chief prosecutor's office towards parliament shouting "Resign, resign", with many carrying torches.
Peter Magyar earlier published a recording of a conversation with Judit Varga, then his wife and Hungary's justice minister, in which she detailed an attempt by aides to Orban's cabinet chief to remove certain parts from documents in a graft case.
The case is centred on former justice ministry state secretary Pal Volner, who was charged in 2022 with accepting bribes from the former head of the Court Bailiffs, Gyorgy Schadl. Both have pleaded not guilty. Prosecutors are seeking jail terms for the pair.
Prosecutors said in a statement they would analyse the tape, which Magyar said he recorded in January 2023, and further evidence would be collected.
"It is legally and physically impossible to eliminate and meddle into prosecution documents," the statement said.
Prosecutors were scheduled to hold a press conference on Thursday.
The allegations come at a politically sensitive time for Orban ahead of European parliamentary elections in June, and follow a sex abuse scandal that brought down two of Orban's political allies - the former president and the former justice minister Judit Varga - last month.
Magyar, 43, a lawyer formerly close to the government, plans to launch a new party to challenge Orban.
"Hungarians thank you ... for coming in the thousands tonight ... to tell those in power that we have had enough," he told protesters in a speech.
On the audio tape, recorded in the then couple's home, and published on Magyar's Facebook page, Varga says aides linked to cabinet chief minister Antal Rogan suggested to prosecutors what should be deleted from documents related to the Volner/Schadl case.
"They told the prosecutors what should be deleted but they (prosecutors) did not entirely follow up on that," Varga is heard on the tape as saying.
Former justice minister Varga, who could not be reached for comment, did not dispute the authenticity of the tape in a post on her Facebook page.
"Peter Magyar made a secret recording of his former spouse, me, in our home and now used this to achieve his political goals. He is not worthy of anybody's trust," she wrote.
Government spokesperson Zoltan Kovacs declined to reply to emailed questions from Reuters about the content of the recording, commenting: "Much ado about nothing."
