It is still unclear what a "No" vote in the referendum would mean for the Dutch government's stance | LOIC VENANCE/AFP/Getty Dutch voters overwhelmingly reject agreement with Ukraine: poll Commission President Juncker says it could spark ‘continental crisis.’

A majority of Dutch voters is opposed to the Netherlands' ratification of the European Union's association agreement with Ukraine, a new poll ahead of an April 6 referendum on the issue showed Saturday.

The poll, conducted by the Dutch public broadcaster's program EenVandaag, is the first barometer on the April 6 vote. It found that over 50 percent of voters "are certain" to reject the Ukraine agreement, while another quarter of respondents said they'll "likely" reject the deal.

Over half of respondents also said they will certainly cast a ballot, while another 17 percent said they'd "most likely" vote. The threshold for the referendum to be taken into account is a turnout of 30 percent.

A rejection of the agreement "could open the doors to a continental crisis" in Europe, Commission President Jean-Claude Juncker told the Dutch newspaper NRC Handelsblad in an interview published on Saturday. He added Russia "stood to benefit the most" from a "No."

"Let's not change the referendum into a vote about Europe," Juncker said. "I sincerely hope that [the Dutch] won't vote no for reasons that have nothing to do with the treaty itself."

In the Netherlands, political campaigns for the referendum have yet to begin.

The Dutch referendum was triggered by a petition organized by the website GeenStijl that reached over 450,000 signatures last September. All Dutch petitions with over 300,000 signatures force the government to put an issue to a vote.

“[Ukraine] is on the brink of full EU membership. We think that the people should be consulted about EU expansion,” Jan Roos, a journalist from GeenStijl, said at the time.

The final parts of the association agreement between the EU and Ukraine were signed in June, 2014 and was then called "a first step towards EU membership" by Ukraine's President Petro Poroshenko. It governs economic and political ties between the bloc and its eastern neighbor.

Ukraine is not formally an applicant to join the EU, although the bloc does recognize Ukraine could ask to become a member in the future.

The association agreement went into force provisionally on January 1, but it has to be ratified by all 28 EU members in order to become permanent.

It is unclear what a "No" vote in the referendum would mean for Dutch policy, as both the government and the country's other leading parties have said they plan to campaign in favor of the association agreement. The referendum result has to be considered by the government, but isn't binding on it.

This article was updated on January 10 to include a comment from European Commission President Jean-Claude Juncker.