* Le Pen says National Front to field lists in 500 towns
* Anti-immigrant party confident of record local vote result
* Voter disillusionment seen buoying score in EU vote
By Mark John
PARIS, Jan 9 (Reuters) - France's anti-immigrant National Front will field candidates in a record 500 towns in March's municipal elections in a bid to break the dominance of mainstream parties in town halls, FN leader Marine Le Pen said on Thursday.
The party is hoping to capitalise on broad disillusionment with President Francois Hollande's Socialist government and the main conservative opposition to make gains both in the local vote and European Parliament elections two months later.
"This is completely new - at least three times as many candidate lists as in the previous local election (in 2008)," Le Pen told foreign journalists at National Front headquarters in the Paris suburb of Nanterre.
"This is the end of the bi-polarisation of French political life," she said of a system long dominated by the Socialist Party and the rival moderate conservative UMP party.
Recent polls show the FN has gained support since the 2012 presidential election in which Le Pen came third with 17.90 percent of the vote, the best first-round score in its history.
However its lack of a geographical base has meant it has fared poorly in previous local elections. At present, it does not control a single town hall and has barely 60 local councillors across the whole country.
By fielding candidates in 500 places the FN will be present in every town of more than 10,000 residents, Le Pen said.
She acknowledged there was little chance of winning any major city outright but cited the 120,000-strong southwestern town of Perpignan, now run by a conservative mayor, as the biggest potential target.
She did not predict how many towns the FN could win, but the party's national secretary Nicholas Bay forecast earlier this week it could capture around 30 towns of between 10,000 and 50,000 residents.
The FN has struggled to get enough credible candidates to stand on its lists and has removed a handful who were caught making racist slurs - undermining Le Pen's efforts to clean up the image of the party once run by her father Jean-Marie.
Le Pen said a quota system requiring parties to field equal numbers of male and female parties was another challenge. "But we are not the only ones facing difficulties there," she added.
The 45-year-old trained lawyer has sought to distance the FN from accusations of anti-Semitism it faced under her father, who was convicted for belittling the Nazi Holocaust. She has stressed the party views French nationals of all ethnic groups as citizens with equal rights.
Her manifesto calls for a sharp reduction in new immigration and tough treatment for illegal migrants, who she says are a costly burden on the welfare state.
Amid wide public scepticism at the European Union's handling of the financial and economic crisis, the FN has seen support grow for its anti-EU line. It wants France to abandon the euro, restore the franc currency, and put continued EU membership to a referendum.
Some recent polls suggest the FN could top the May European Parliament poll with about 25 percent of the vote as part of a wider surge of populist anti-EU parties across Europe.
While it is too early to predict what impact a bigger group of FN and like-minded parties could have in the EU legislature, Le Pen said her goal was to end the system of pooling national sovereignty in Europe.
"I only expect one thing from the European system - that it explodes," she said. (Editing by Paul Taylor)