"If you come to Hungary," reads a giant roadside billboard, "don't take the jobs of Hungarians!"
The billboards have been ordered by the government, at taxpayers' expense, and are going up all over the country.
Liberal and left-wing opposition parties are so incensed by a message they believe whips up xenophobia, that activists have started defacing every poster they find.
The original text of this poster, next to the Obuda cemetery in Budapest, reads: "If you come to Hungary, you have to keep our laws."
"Our laws" has been painted over, and the words "National Consultation on Migration and Terrorism" have been altered to read: "National Insult on Migration and Terrorism".
Another billboard has been defaced even more drastically, with the slogan: "See (what's going on), don't just stare!".
The billboard campaign is part of a government effort to win public support for tough new laws, expected after the summer break, aimed at limiting migration to Hungary.
These changes may include the erection of a border fence along Hungary's southern border, and returning asylum seekers to Serbia.
Now critics of the government's moves have found an ally, in the form of the regional office of the UN High Commissioner for Refugees.
To mark World Refugee Day on 20 June, the UNHCR has prepared its own set of giant billboards, highlighting refugees who have successfully integrated into Hungarian society.
This poster features Zeeshan, a Pakistani man who plays in the enthusiastic, but little known, national cricket team.
"I want to play well for this country," his message reads.
Another UN poster features Sophie, originally from Togo, and now a nanny in a Hungarian kindergarten.
"The children are full of trust. They have no prejudices," her caption reads.
"We want to live here, and that's why we opened our restaurant," announces Begum Ali, who runs a small Bangladeshi family restaurant near Budapest's East Station.
The UN describes its posters as an "interesting dialogue with the Hungarian government's anti-immigrant billboard campaign".
Prime Minister Viktor Orban's government points out that its billboards were part of a voter survey on immigration sent to eight million Hungarians.
While there has been a marked increase in the number of migrants arriving in Hungary, tens of thousands of Hungarians have been leaving the country, too.