Brooklyn Republican state Sen. Martin Golden yesterday urged the feds to unmask the name of mystery GOP “chairman#1” in the Malcolm Smith bribery case.

“Descriptions within the sealed complaint raise serious questions concerning the integrity of said county chairman,” Golden said in a letter to Manhattan US Attorney Preet Bharara.

“Based on the descriptions in the complaint, I believe, once revealed, county chairman#1 should, if he has not already, resign his party post.”

Bharara’s office declined comment.

GOP officials were furious with Golden’s letter, because a close reading of the criminal complaint provides no evidence that the mystery “chairman#1” did anything wrong, and they feared Golden’s statement amounted to slandering an innocent GOP county chairman.

The criminal complaint charges Smith, Councilman Dan Halloran, Bronx GOP ex-Chairman Jay Savino and Queens GOP Vice Chairman Vince Tabone with a bribery scheme to sell Democrat Smith Republican ballot access in the mayoral race.

“Shame on Senator Golden, a former police officer who should know better than interfering with an ongoing federal investigation,” said Manhattan GOP Chairman Dan Isaacs.