German far-right party Alternative fur Deutschland (AfD) has voted to campaign for Germany's withdrawal from the European Union if Brussels fails to meet its demands for reform.

While rank and file members insisted the so-called 'Dexit' be included in the party manifesto, party leaders approached the idea with caution, aware of the country's majority support for the EU.

"When you play with the idea of a Dexit, you have to ask yourself if this is Utopia and if we should better stay realists," party leader Alexander Gauland said in a speech on Sunday.

The party spent the first two days of the conference selecting candidates for the European elections in May.

Outside the conference hall in the Eastern city of Riesa, anti-fascist demonstrators gathered to protest the AfD's presence. The mostly peaceful rally saw isolated clashes between police and right-wing groups.

Riesa has been the site of several neo-Nazi incidents and is home to the right-wing NPD party and publishing house "Deutsche Stimme".