Traditional Unionist leader Jim Allister has been barred from speaking in the Assembly for a month.
The 'gag' came after the North Antrim MLA clashed with Ulster Unionist deputy speaker Roy Beggs in the chamber last week.
It is believed to be the first month-long ban imposed on an MLA, although the period includes the Halloween recess.
The Speaker's Office decided the punishment had to be longer than his last ban in 2011.
Mr Allister blamed the latest gag on deputy principal Speaker Mitchel McLaughlin, after he reminded MLAs on Monday that the Sinn Fein member had claimed in 2005 that the IRA murder of Belfast woman Jean McConville was not a crime.
Mr McLaughlin failed to be elected Speaker after failing to get DUP support.
Mr Allister described his speaking ban as "a gross and disproportionate infringement of the rights of those who elected me".
A spokesperson for the Speaker's Office said: "The member has already had several warnings on previous occasions."