The Australian Building and Construction Commission has launched its first legal action relating to a waterfront dispute, alleging union members made death threats against workers who tried to cross a picket line in Fremantle.

The new head of the Construction, Forestry, Maritime, Mining and Energy Union, West Australian official Christy Cain, is named in a statement of claim alleging that union members yelled “scab” and “dog” and “you’ll end up dead if you keep going like this”.