The so-called ‘super-union’ would incorporate two million UK workers from two of the biggest unions.
The vote follows a special T&G meeting that debated how a merger would affect the trade union movement and union links with the Labour Party.
The super-union proposal will be balloted in February of next year.
T&G general secretary Tony Woodley said the merger represented “working class unity”.
Amicus has 1.2 million members and the T&G has 800,000.