Over 600 Google employees have signed a manifesto that asks company leaders to retract the corporate vaccine mandate and calls on fellow workers to "oppose the mandate as a matter of principle" as the return-to-work deadline nears.

In response to President Joe Biden's order mandating vaccines for businesses with more than 100 employees, many US companies have stated that they'll institute the vaccine requirement themselves. Among them is Google, whose vice president of security has long made clear that the company would be mandating vaccines.

As a result, CNBC reports, a manifesto has been circulated around Google and signed by hundreds of employees. It calls for a mandate that's "inclusive of all Googlers" and urges workers to "oppose the mandate as a matter of principle."

Google employees were given until Nov. 12 to request exemptions for medical conditions or "religious beliefs," as company leadership plans for staff to return to in-office work for three days a week starting Jan. 10 of next year.

"As we've stated to all our employees and the author of this document," a spokesperson for Google told CNBC, "our vaccination requirements are one of the most important ways we can keep our workforce safe and keep our services running. We firmly stand behind our vaccination policy."

The letter's signatories only represent a small fraction of Google's total workforce. Google has asked its more than 150,000 employees to upload vaccination statuses to its internal systems by Dec. 3, whether or not they're planning to come into the physical offices, according to internal documents viewed by CNBC.