The treasurer of the Working Families Party, which is under scrutiny for possibly skirting campaign-finance laws for favored candidates, abruptly resigned last month, sources said yesterday.

Insiders denied that Mike McGuire’s exit had anything to do with the Campaign Finance Board looking into improper “coordination” between campaigns and outside groups, as first revealed in The Post.

The new treasurer is Dorothy Siegel, a member of the Executive Committee.

McGuire did not return a call for comment.