The Internal Revenue Service has filed a lien for more than $37,000 in back taxes against the Arlington-based National Socialist White People's Party, a self-described racist, extreme right-wing organization.

A party spokesman said yesterday the group has been notified that seizure of its headquarters, an aging, two-story building four blocks from the Arlington County Courthouse, is imminent.

Federal tax officials filed the lien last month in Arlington Circuit Court.

After two months of unsuccessful attempts to raise the money from members, party leader Matt Koehl met on Monday with IRS representatives, but failed to win an extension of the deadline. According to party spokesman Martin Kerr, the matter has now been turned over to the IRS enforcement division.

"We gave them what we could, but they didn't come through with an extension. They don't want the money, they want blood," said Kerr, seated in the party's cramped front office, surrounded by anti-Semitic literature and a portrait of Adolf Hitler.

According to Kerr, the party claims it should not have to pay taxes on what it says were unsolicited political donations. Kerr attributes IRS scrutiny to a Reagan administration vendetta against the group.

Earlier this year, an urgent letter signed by party "Commander Matt Koehl" went out to members and supporters soliciting financial help. "March . . .that's the date the IRS picked to seize and padlock party headquarters in Arlington," the letter said. The letter also referred to two properties owned by the organization in the Midwest.

These appear to be lean times for the 23-year-old organization. Membership is "very small," according to spokesman Kerr, and income has not kept pace with party expenses during the last two years. In addition to its small, swastika-bedecked headquarters, the party rents space over a dentist's office next door.

"He's not a member of the party," Kerr said Monday, "but nobody knows it, so he keeps getting his windows knocked out."