Budapest (AFP) - Hungary's populist strongman Viktor Orban was banking on voters Sunday to defy the European Union and reject its troubled refugee quota plan, but low turnout threatened to taint his camp's expected referendum win.
Surveys showed the referendum turnout might not reach the required 50-percent threshold and therefore be deemed invalid.
But Orban has already downplayed the political significance of the eventual turnout and said there would be "legal consequences" regardless of the outcome.
Orban's right-wing government has led an expensive media offensive urging the eight-million-strong electorate to spurn the EU's migrant quota deal, which wants to share migrants around the 28 member states via mandatory quotas without the consent of national parliaments.
"A valid referendum is always better than an invalid one, but the legal consequences will be the same," he said on Sunday.
"There is only one condition for this: that there are more 'No' votes than 'Yes' votes."
The firebrand leader has emerged as the standard-bearer of those opposed to German Chancellor Angela Merkel's "open-door" policy, in the wake of the bloc's worst migration crisis since 1945.
Polling stations opened at 0400 GMT and close at 1700 GMT, with results expected later in the evening. By 5.30 pm (1530 GMT), turnout was just below 40 percent, according to the national election office.
Opposition parties and rights groups had called on Hungarians to boycott the referendum or spoil their ballot.
"I am European so I cast my vote but I spoilt it because I don't believe in this government. I want control of the migrant flow but not in this way," a hotel owner in Budapest told AFP.
- 'Dangerous game' -
The EU migrant quota proposal -- spearheaded by Germany and approved by most EU governments last year after antagonistic debates -- seeks to ease pressure on frontline countries Italy and Greece, where most migrants enter the EU.
But implementation has been slow. Eastern and central European nations are vehemently opposed to the plan aimed at relocating 160,000 people, many having fled war in Syria.
Even as Hungarians voted, neighbouring Austria's Foreign Minister Sebastian Kurz said the EU should stop clinging to its troubled plan.
"The target is totally unrealistic," he told the German daily Welt am Sonntag, warning that disagreements over the plan could threaten "the cohesion of the entire European Union".
Hungary has not accepted a single one of the 1,294 refugees allocated to it under the scheme and instead joined Slovakia in filing a legal challenge against it.
The referendum threatens to further split the quarrelling bloc, already weakened by Britain's decision in June to leave the union -- a decision Orban has blamed on the EU's handling of the migrant crisis.
European Parliament president Martin Schulz warned Sunday that Hungary was playing "a dangerous game".
To cement his power at home, Orban "plays with the EU's founding principle: he questions Europe's legal basis -- which Hungary was involved in creating," Schulz told German media.
- 'Brussels elite' -
The referendum asks voters: "Do you want the EU to be able to mandate the obligatory resettlement of non-Hungarian citizens into Hungary even without the approval of the National Assembly?"
In an editorial, Orban warned on Saturday that Hungarians had "a duty" to fight the failed "liberal methods" of the "Brussels elite".
"It's true that the campaign was exaggerated but no-one can tell me if these migrants really are refugees of war," Zoltan, a 38-year-old lawyer and 'No' voter, told AFP.
More than 400,000 refugees trekked through Hungary toward northern Europe in 2015 before Hungary sealed off its southern borders with razor wire in the autumn and brought in tough anti-migrant laws, reducing the flow to a trickle.
Other countries on the so-called Balkan migrant trail followed suit, leading to some 60,000 migrants now being stranded in Greece.
The EU said last week it hoped to relocate half of them by the end of 2017.
A deal struck in March with Ankara to halt the influx looks shaky in the wake of a coup attempt in Turkey in July.
German Interior Minister Thomas de Maiziere meanwhile said Sunday that Berlin wants to reinstate EU rules, suspended in 2011, which oblige asylum-seekers to be sent back to Greece as the first EU country they reached.
"We will take up discussions on this in a meeting with (EU) interior ministers" later in October, he told the Greek daily Kathimerini.