France's Front National leader Marine Le Pen will meet other far-right and eurosceptic leaders on Wednesday in an attempt to create a powerful bloc in the European parliament.

However, Le Pen ruled out joining forces with the extreme-right Golden Dawn in Greece, the Hungarian party Jobbik or Ataka in Bulgaria.

Having spent years trying to shake off the FN's reputation as a refuge for Nazi sympathisers – her father, the party's founder Jean-Marie Le Pen, once dismissed the Holocaust as a "detail" – Le Pen said she did not envisage meeting newly elected German MEP Udo Voigt of the neo-Nazi NPD.

"There are a whole group of movements that, in my opinion, are interested in taking part in a large political force whose aim would be to prevent any new move towards European federalism," she told a press conference on Tuesday morning.

After Reuters reported that the FN was considering an alliance with certain extreme-right European groups, Le Pen issued an angry statement. "Following a serious error, Reuters suggested that I envisaged alliances with Jobbik and Golden Dawn. I have declared exactly the opposite...," she wrote. "Asked 'with whom will you not ally yourselves?', I replied: Jobbik, Ataka and Golden Dawn among others."

Le Pen requires the support of 25 MEPs from seven different countries to form a political group in the European parliament.

Feeling newly empowered after her party won 25% of the European vote in France, Le Pen repeated her call for the dissolution of the French Assemblée Nationale.

Le Pen insisted the party's score was an unqualified victory despite an abstention rate of 57%. She demanded that France call a halt to talks between the EU and the US to create a vast free market, known as the Transatlantic Trade Treaty.

"I clearly call on the president of the Republic, firstly the dissolution of the Assemblée Nationale, because you know it is no longer at all representative of the French people," Le Pen said.

"I also demand that he does three things to take Sunday's vote into account: firstly, France halts the transatlantic treaty, secondly, France states its veto of Turkey's entry into the European Union and, thirdly, he nationalises Alstom, contrary to the rules of the European Union, to save this strategic company."

Alstom is the struggling French conglomerate that makes high-speed TGV trains and is currently the subject of takeover bids by General Electric and Siemens.

Le Pen, who has described the FN as "France's first party" following Sunday's vote, was speaking as the mainstream opposition party, the UMP – which is engulfed in a damaging campaign funding scandal – appeared on the point of implosion after its leader Jean-François Copé announced he would stand down next month.

Copé and the centre-right party were plunged into crisis after damaging new revelations emerged over millions of euros paid to a communications company in return for allegedly forged invoices for former president Nicolas Sarkozy's failed re-election campaign in 2012 that were charged as party expenses. The communication agency, Bygmalion, is run by two of Copé's close friends.

Earlier, a lawyer for Bygmalion alleged the company had falsified €10m (£8m) in invoices to the UMP, but added: "Services were provided ... but they should have been charged to the campaign of presidential candidate Nicolas Sarkozy."