The Crofting Commission's convener has submitted an official complaint about the minister in charge of crofting.
Colin Kennedy has refused to stand down from his post, despite coming under pressure from the government to resign following a dispute over common grazings.
He accuses the Rural Economy Secretary Fergus Ewing of being in breach of the ministerial code.
The government has confirmed it is investigating the complaint.
It added that crofting remained in Mr Ewing's portfolio.
Last month, the board of crofting's regulatory body apologised for its handling of the dispute with crofters. It also asked Mr Kennedy to resign.
The dispute relates to the running of common grazings, including those at Mangersta and Upper Coll on Lewis.