AMSTERDAM, Jan 9 (Reuters) - European Commission President Jean-Claude Juncker has warned that a Dutch advisory referendum in April on the bloc's association agreement with Ukraine could lead to a "continental crisis" if voters reject the treaty.
In an interview published on Saturday by the Dutch daily NRC Handelsblad, Juncker said Russia would "pluck the fruits" of a vote in the Netherlands against deepened ties between the European Union and Ukraine.
The April 6 referendum, whose result will be non-binding, was triggered by the raucously anti-European satirical website GeenStijl last year, which collected more than the 300,000 signatures needed under the law to force a vote.
The website admitted that its reasons for seeking the referendum, to be held during the current Dutch presidency of the bloc, had less to do with its views on the EU's ties with Ukraine than with its desire for a vote on the bloc itself.
"I want the Dutch to understand that the importance of this question goes beyond the Netherlands," NRC quoted Juncker as saying.
"I don't believe the Dutch will say no, because it would open the door to a big continental crisis," he added. "Russia would pluck the fruits of an easy victory."
A founding signatory of the Treaty of Rome that created the incipient EU in 1957, the Netherlands has cooled on European integration as fears about high immigration, slow growth and economic insecurity have grown.
While most Dutch parties are pro-European, the anti-EU, anti-immigration and anti-Muslim Freedom Party of right-wing populist Geert Wilders is leading in polls and would win more seats than the entire Liberal-Labour coalition if elections were held now.
But the association agreement, seen as a key step in the process of bringing the one-time Soviet republic out of Russia's orbit and closer to the EU's, could test the forces of anti-EU populism.
Russian President Vladimir Putin is an unpopular figure in the Netherlands, where he is widely blamed for the July 2014 downing of Flight MH17 over eastern Ukraine that killed 298 people, two-thirds of them Dutch.
Relations between Russia and the West hit a post-Cold War low over Ukraine, where Moscow annexed Crimea from Kiev last year and stands accused by Washington and Brussels of driving a separatist pro-Russian revolt in the east.
In November, Ukrainian President Petro Poroshenko said campaigners for a referendum were unwitting pawns of Putin. It is unclear how many signatories of the petition - 430,000 in a nation of 17 million - will turn out to vote. (Reporting By Thomas Escritt; Editing by Tom Heneghan)