* PM Orban's billboards feature Soros's smiling image
* Hungarian Jews have called for halt of government campaign
* Israeli PM due to visit Hungary next week
* Government says end of campaign has nothing to do with visit
BUDAPEST, July 13 (Reuters) - An anti-migrant billboard campaign by the Hungarian government that features the image of U.S. financier George Soros will come to an end on Saturday, the government spokesman said on Thursday.
The billboards and full-page media ads that have appeared across Hungary depict a smiling Soros -- a vocal critic of Prime Minister Viktor Orban's right-wing government -- with the caption: "Don't let Soros have the last laugh."
Some Soros billboards have been defaced with graffiti that reads "stinking Jew".
The Federation of Hungarian Jewish Federations (Mazsihisz) has urged Orban to halt the campaign, which a spokesman for Soros said earlier this week was reminiscent of "Europe's darkest hours". Orban's government has strongly denied that the billboard campaign is anti-Semitic.
Government spokesman Zoltan Kovacs told Reuters the campaign, which was a follow-up to the launch by Orban of a "national consultation" on issues of foreign influence and mass immigration, would expire on July 15.
"The six-week follow-up campaign will run out on July 15," Kovacs said in an emailed reply to Reuters questions.
Soros, a Hungarian-born Jew who has spent a large part of his fortune funding pro-democracy and human rights groups, has repeatedly been targeted by Hungary's right-wing government, in particular over his support for more open immigration.
Kovacs said the campaign's end-date had nothing to do with the visit of Israeli Prime Minister Benjamin Netanyahu to Budapest next week. He declined to say how much the massive billboard campaign had cost.
Orban will seek a third consecutive term at elections in April 2018.
He launched the poster campaign portraying Soros as an enemy of Hungary after voters who responded to the government's "national consultation" rejected both "foreign influence" and mass immigration.
Israel's ambassador to Hungary initially denounced the campaign, saying it "evokes sad memories but also sows hatred and fear", an apparent reference to Hungary's part in the deportation of 500,000 Jews during the Holocaust.
But the Israeli foreign ministry later issued a "clarification" saying that Soros was a legitimate target for criticism, a move that appeared designed to align Israel more closely with Hungary ahead of Netanyahu's visit to Budapest.
Israel is normally quick to denounce anti-Semitism or threats to Jewish communities anywhere in the world. While it made that point in the statement, it chose to focus on the threat it believes Soros poses to Israeli democracy.
Among the organisations Soros funds is Human Rights Watch, which is frequently critical of Israel's occupation of the West Bank and its policies towards the Palestinians.
Soros, 86, who emigrated from Hungary after World War Two, made his fortune in the United States and has long supported groups promoting liberal, democratic and open-border values in eastern Europe.
Orban has long proclaimed zero tolerance for anti-Semitism, though he has more recently risked angering Jews with remarks apparently meant to court far-right voters.
In a statement on Thursday, former United Nations chief Kofi Annan expressed deep concern about the poster campaign, which he said played on "xenophobic sentiments".
Noting the thousands of Hungarians who emigrated after the 1956 revolution, Annan said he hoped Hungary would "find a way out of its current isolation and back to the values enshrined in the U.N. refugee convention and U.N. charter for human rights". (Reporting by Krisztina Than; Editing by Catherine Evans)