The Justice and Law Enforcement Ministry apologises for erroneously claiming that a video recording showed a test detonation by far-right terrorists, the government spokesman's office announced after the ministry briefed Prime Minister Gordon Bajnai on the footage on Friday.

The film in fact depicted a test explosion in a field near Bonyhád, south Hungary in 2007, which was carried out by five chemistry students who later received suspended sentences.

National Bureau of Investigation head Attila Petőfi offered his resignation for having asserted that the footage, which was found on the server of the Hungarian Arrows, was of a test carried out by the extreme nationalist group.

Justice and Law Enforcement Minister Tibor Draskovics declined Petőfi's offer to resign, but cautioned him and a deputy for failing to provide accurate information.

Government spokeswoman Bernadett Budai said Bajnai's confidence in Draskovics is unwavering.

Fidesz MP Zoltán Balog told reporters in Budapest on Sunday that "everyone who took part in fabricating evidence, gave orders, or knew about the case, is now unfit and unworthy of running the country, and should leave public life."