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.

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 to 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.

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.