The nationalist and anti-migration Alternative for Germany hopes to increase its representation in the EU legislature in the May 26 election. The party, known by its German acronym AfD, won seven seats in 2014 but currently holds only one after internal divisions saw its other lawmakers leave.
The party platform approved by delegates for this year's election stated that if the party's "fundamental reform approaches" can't be realized "within a reasonable period," Germany's withdrawal from the EU or the bloc's dissolution and the founding of a looser European economic alliance would be "necessary as a last resort," news agency dpa reported.
An initial draft had called for a possible German withdrawal if reform couldn't be achieved within one five-year European Parliament term.
Party leaders argued against a fixed date at a party convention in the eastern town of Riesa. AfD co-leader Alexander Gauland said it "is not smart to go into the election with a maximum demand in such a situation."
He argued that, if Britain's planned departure from the EU in late March causes short-term turbulence and economic problems for the British, it could influence voters in Germany.
Gauland said the chances of reducing the EU to a purely economic community are good but it would take more than one parliamentary term.
AfD entered Germany's national parliament in 2017 and is currently the biggest opposition party there.