The internal activism at Google is only growing it seems as the company has fired another employee for sending browser pop-ups about the labour rights at the company.

She becomes the fifth staffer fired for being involved in internal activism, reports The Verge.

Spiers was tasked with sending web browser notifications as pop-ups within the company.

"I created a little notification, only a few lines of code, that pops up in the corner of the browser whenever my coworkers visited the union busters' website or the community guidelines policy. The notification said: 'Googlers have the right to participate in protected concerted activities,'" she wrote in a post on Medium.

After releasing the browser message, she was put on administrative leave and was told that she was being fired from the company.

"Google's response to this was to suspend me immediately and without warning. This was the week of Thanksgiving, the same day they fired the Thanksgiving Four. They also dragged me into three separate interrogations with very little warning each time," Spiers posted.

"I was interrogated about separate other organizing activities, and asked (eight times) if I had an intention to disrupt the workplace. The interrogations were extremely aggressive and illegal.

"They wouldn't let me consult with anyone, including a lawyer, and relentlessly pressured me to incriminate myself and any coworkers I had talked to about exercising my rights at work," she wrote.

A Google spokesperson said: "We dismissed an employee who abused privileged access to modify an internal security tool. This was a serious violation".

According to Spiers, Google has overreacted in an egregious, illegal, and discriminatory manner.

"The notification I wrote had no negative effect on our users or other employees and Google will do its best to justify my firing in a way that pits workers against each other but they can't hide behind this fabricated logic forever," she said.

Meanwhile, the US government has launched a probe into Google over its labour practices following a complaint from four employees who have been fired by the tech giant.

The four workers who filed a lawsuit against the company claimed they were fired from Google for engaging in legally protected labour organizing, reports CNN Business.

The National Labor Relations Board has begun a formal probe into the complaint.

The tech giant has been accused of "union busting" and retaliatory behaviour after it sacked four employees for allegedly violating the company's data security policies.

In a statement, Google said it dismissed four individuals who were engaged in intentional and often repeated violations of its longstanding data security policies.

Google is in the midst of controversy over its strained relationship with employees.

The new CEO of Alphabet Sundar Pichai faces extreme challenges as Google stares at several high-profile external probes into its alleged anti-trust market and data practices -- from the US to the European Union regulators -- including internal tensions with staff over discrimination at work and HR transparency.