The far-right Danish People's party (DPP) triumphed in the European elections, winning Denmark's biggest share of the vote as EU-sceptic parties from across the Nordic countries gained further ground in the European parliament.

The DPP, which had campaigned to reclaim border controls and curb benefits to other EU citizens living in Denmark, won nearly 27% of the vote and doubled its number of MEPs from two to four.

Denmark's centre-right opposition party Venstre, its leader dogged by an expenses scandal in recent weeks, was one of the big losers, dropping one of its seats and heading for its worst EU election result in 25 years.

"I see it as a clear indication that the Danes want the EU back on track," said Morten Messerschmidt, the DPP's leading candidate. "Around Europe we are some democratic, civilised but EU critical parties – such as the Danish People's Party, such as the British Conservatives and others – who now try to steer back EU to what it is all about, to find a solution to trade, environment and energy challenges we have across borders, but not an EU that's going to interfere in everything."

In Sweden, the governing Moderate party suffered a disastrous night and was overtaken by the Greens, now Sweden's second-biggest party in the European parliament. The populist far-right Sweden Democrats gained their first seat, as did the Feminist Initiative whose MEP will be the first member of the European parliament to be represented by a feminist party.

"The Feminist Initiative party is a real sensation," wrote political commentator Ewa Stenberg from the the newspaper Dagens Nyheter. "The party has shot up like a rocket in public opinion since the beginning of the year. They have been carried both by a feminist wave and an anti-racist one."

The leader of the Moderates, Swedish prime minister Fredrik Reinfeldt, said it had been hard being a governing party. "It has been an evening where the voters haven't rewarded parties which believe in European co-operation," Reinfeldt told Swedish TV.

Finland's anti-immigration Finns party – previously known as the True Finns – increased its number of MEPs to two, but its share of the vote (13%) didn't match its success in the last national election when it won 19%. The prime minister's conservative National Coalition remained Finland's largest party in Europe with 22.6% and kept its three seats.