Employees at Google and other units of parent firm Alphabet announced the creation Monday of a union, stepping up a period of activism targeting Silicon Valley giants.

The Alphabet Workers Union, affiliated with the Communications Workers of America, aims to represent well-compensated tech workers as well as temporary workers and contractors, according to a statement.

The new labor group is focusing not only on pay and benefits as most unions but also a role in ethical decisions by the tech giant and protection from arbitrary firings for activism.

"We hope to create a democratic process for workers to wield decision-making power; promote social, economic, and environmental justice; and end the unfair disparities between TVCs (temporary, vendors and contractors) and FTEs (full time employees)," the union's website said.

As of the end of December, the union had some 200 members.

Large tech firms, which offer generous compensation to software engineers and other skilled workers, have largely avoided labor drives but have faced growing unrest over workplaces issues in recent years.

At Amazon, which has tens of thousands of warehouse workers, organizing drives have focused on working conditions and safety during the pandemic.

One of the catalysts at Google was the recent firing of Timnit Gebru, a Black artificial intelligence ethics researcher and outspoken diversity activist.

The company also faced a backlash from employees over its involvement with a Pentagon project known as Project Maven, which Google eventually ended.

"This union builds upon years of courageous organizing by Google workers," said Nicki Anselmo, a Google program manager and union member.

"From... opposing Project Maven, to protesting the egregious, multimillion dollar payouts that have been given to executives who’ve committed sexual harassment, we’ve seen first-hand that Alphabet responds when we act collectively."

Asked about the organizing effort, Google's director of people operations Kara Silverstein,said in a statement: "We've always worked hard to create a supportive and rewarding workplace for our workforce.

"Of course our employees have protected labor rights that we support.  But as we’ve always done, we’ll continue engaging directly with all our employees.” 

The move comes with Google and other tech giants under heightened scrutiny by antitrust enforcers in the US and elsewhere for their growing dominance of key economic sectors.