THE Service Employees International Union is set to return to US union federation the AFL-CIO after 20 years.

The union groups’ executive boards unanimously approved the combination on Wednesday with the formal announcement due last night at a roundtable in Austin, Texas, with workers who are attempting to unionise. 

There are roughly two million SEIU workers in the healthcare, janitorial and food services sectors, among others. 

Their addition would bring the total number of AFL-CIO members to nearly 15 million, helping increase the political heft of a federation already composed of 60 unions.

AFL-CIO president Liz Shuler said: “We are amassing our forces, building our strength and our power before the inauguration” of Donald Trump as the country’s new president later in January. 

She added: “Working people will continue to demand that our voices be heard.”

SEIU president April Verrett said: “We are determined to organise in unprecedented ways — and that requires real power.”

The SEIU, along with the Teamsters union, left the AFL-CIO in 2005. 

Union leaders said that by having the SEIU rejoin the AFL-CIO, they will be better equipped to share research and best practices on organising to overcome resistance to unionisation by some employers and government officials.