The Construction, Forestry, Maritime, Mining and Energy Union is facing a damaging internal war over John Setka, with the union's mining division publicly attacking the Victorian leader for poaching members from another division.

The mining union's central council on Thursday unanimously supported a motion condemning Mr Setka's Victorian construction union for its "unprincipled actions" in poaching members from the manufacturing division and supported "without reservation" any measures to enforce the division's autonomy.