The US government is investigating Google after accusing the tech firm of paying women less than men.
A US Department of Labor official disclosed the allegations during a Friday court hearing in San Francisco.
"We found systemic compensation disparities against women pretty much across the entire workforce," Janette Wipper, a Labor Department regional director, is quoted as testifying.
The department is able to look at Google's remuneration as the firm is a government contractor.
Google has denied the allegations, saying in a statement that it conducts a "comprehensive and robust" analysis of its pay across genders every year and found "no gender pay gap".
The Silicon Valley firm has tried to make its workforce more inclusive but like many tech companies remains largely male-dominated.
Only 19 percent of Google’s technology jobs are reportedly held by women while around a third of the company's 70,000 workers are female.
The Labor Department investigation stems from a January lawsuit seeking to prohibit Google working for the US government unless the company complied with an audit of its employee-compensation records.
Google said it had made a number of the records available but said some had to be withheld to protect employees' privacy.