The National Union of Workers was first formed in 1991 following a series of amalgamations of unions from 1989 onwards: the Federated Storemen & Packers Union; the Federated Miller & Manufacturing Grocers Employees Association of Australia; the Rubber and Allied workers Union;the Pastrycook, Biscuit Makers' and Allied Industries Union; the Commercial Travellers Guild. The six unions which currently form the NUW include the Federated Storemen and Packers Union; Federated Rubber and Allied Workers Union; Federated Cold Storage and Meat Preserving Employees' Union; Federated Millers and Manufacturing Grocers Union; Commonwealth Foremen's Association; United Sales Representatives and Commercial Travellers Guild.

On 11 November 2019 the National Union of Workers and United Voice merged to create the United Workers Union.