The Freedom Party (or PVV), led by Geert Wilders, is opposed to what it calls the country's "Islamisation".
General elections have been called following the collapse of the Dutch government in a dispute over the deployment of troops in Afghanistan.
Last year, the PVV came second in the country's polls to the EU parliament.
'Springboard' situation
The PVV fielded candidates in municipal elections in two cities: Almere, a city of some 200,000 inhabitants east of the capital Amsterdam, where its looks set to be the biggest party, and The Hague, where it was in second place.
Preliminary results show that in Almere, it has won 21% of the vote, while in The Hague, it has won eight seats, behind the Dutch Labour Party which had 10 seats.
"What is possible in The Hague and Almere is possible all over the country. It's a springboard for our victory," Mr Wilders told supporters in Almere.
Last year, the PVV came second in European elections in the Netherlands, winning 15% of the vote.
BBC News
