"We represent the workers who manufacture and distribute the food, beverages and pharmaceuticals we all rely on.”

NUW to be deregistered

The ballot result means the mega-union is all but a reality, with the Fair Work Commission now expected to approve the amalgamation.

The NUW, which has a militant reputation and recently secured pay rises of up to 22 per cent for Chemist Warehouse workers, will be deregistered as part of the merger and its members folded into the larger United Voice.

Labor sources say the merger could shake up the party's factional politics and boost the power of the Left, with the NUW nominally from the Labor Right while United Voice is a key player in the Labor Left.

Mr Kennedy said the new union, which will be bigger than the Construction, Forestry, Maritime, Mining and Energy Union, would be "transformative" and "put workers at the centre of our economic and political system".

While most unions operate with state branch divisions, the UWU will have one single leadership team with different industry and campaigning teams.

About 45,000 members took part in the merger ballot, which went on for 35 days across both unions.

United Voice secretary Jo-anne Schofield said the ballot result reflected the union's ambition to ensure members are "at the heart of everything we do.”

“Our members want a powerful voice, to take action on inequality and to win jobs they can count on. The job for us now is to get to work and deliver for our members, as one bigger, stronger union.”