* Le Pen says banks stifling political opposition
* Vows to file complaints against banks (Adds Le Pen news conference)
NANTERRE/PARIS, Nov 22 (Reuters) - French far-right leader Marine Le Pen accused banks on Wednesday of closing accounts that belong to her and her party, saying she has been the victim of a "banking fatwa" meant to silence her National Front.
The 49-year-old is smarting from defeat in presidential and parliamentary elections this year, during which she already accused French banks of being politically biased for not giving loans to finance her campaigns.
"This is an attempt to suffocate an opposition party and no democrat should accept that," Le Pen told a news conference, calling on President Emmanuel Macron and other political parties to back the National Front.
The far-right leader, who is struggling with feuding in her party after May's election loss to Macron, said the National Front would file a complaint against Societe Generale and its subsidiary Credit du Nord. She would also file a complaint against HSBC over closure of a personal account of hers.
The FN says Societe Generale closed its accounts in November and that when the central bank ordered a subsidiary, Credit du Nord, to manage an account for the party, the bank refused to process check and credit card payments.
Societe Generale and HSBC both said they could not comment due to banking confidentiality rules. Neither has confirmed or denied closing FN accounts or those of Le Pen.
In France, banks are allowed to decide to close accounts with advance notice, and do not have to say why. But holding an account is a right and a customer can ask the Bank of France to designate a bank that would be forced to open one. The designated bank can choose to limit the use of the account to basic banking services.
The FN spent 12.5 million euros ($14.70 million) on the presidential election alone.
Party supporters have since been asked in an online campaign to directly lend it money.
Few politicians have commented on the FN's banking woes. Mael de Calan, a contender for the leadership of the Republicans, a conservative party, told BFM TV he was shocked a bank would ask a political party to close its accounts.
($1 = 0.8503 euros) (Additional reporting by Brian Love, Mathieu Prottard, Maya Nikolaeva, Sophie Louet and Yann Le Guernigou; Editing by Peter Graff)