Gov. David Paterson called a special election for March 16 to determine who will replace the Queens borough Democrat, whose ouster leaves the state Senate with 31 Democrats and 30 Republicans, The New York Times reported.
Monserrate said he intends to try to regain his seat in the special election and his attorneys also are seeking a remedy in federal court, the newspaper said.
"The New York state Senate does not have the constitutional and legal authority to expel Senator Monserrate," said Norman Siegel, one of the ousted lawmaker's lawyers. "And even if they did, their actions have not been consistent with due process of law."
Monserrate was arrested in December 2008 and convicted on a misdemeanor count last fall. He avoided conviction on a felony charge that he cut his companion on the face with a broken glass.
Monserrate is the first state lawmaker expelled in New York since the 1920s, when six assemblymen who were members of the Socialist Party of America were booted, the Times said.