Budapest (AFP) - Hungary is set to launch another state "national consultation" about US financier and philanthropist George Soros, the government said Tuesday, six months before expected general elections.

The campaign would be to investigate public views on the "Soros plan", and would likely be launched next month, government spokesman Bence Tuzson told public radio, without giving further details.

Last week a top official in the ruling Fidesz party, Lajos Kosa, said that this "Soros plan" includes Europe accepting a million migrants per year and the demolition of Hungary's anti-migrant border fences.

Prime Minister Viktor Orban has regularly attacked the Hungarian-born Soros in the last year, calling him a "public enemy" for his alleged backing of uncontrolled mass immigration.

A national consultation earlier this year also focused on Soros, seen as a liberal bogeyman by Budapest who funds a raft of civil society groups in central and eastern Europe.

An image of the 87-year-old laughing adorned billboard posters alongside a message urging Hungarians "not to let Soros have the last laugh".

The posters, some of which were daubed with anti-Semitic graffiti, were widely condemned including by Soros himself and Hungary's main Jewish organisation, which called them "poisonous".

The drive is the latest of a series of taxpayer-funded "national consultations" by Orban's government comprising questionnaires sent to households and accompanying mass media "public information" campaigns.

The first one, in 2015, included a questionnaire asking households about "immigration and terrorism".

That survey was sharply criticised, notably by the UN refugee agency UNHCR which expressed "shock" at its questions and said it could boost xenophobia in the EU country.

Another campaign titled "Let's Stop Brussels" asked citizens for advice on how to deal with European Union policies that the government said threatened Hungarians' independence.

Hungarian media reported Tuesday that Orban told a recent closed party meeting immigration would be the main theme of the run-up to the next election, likely to be held in April.