The women, one former and two current employees from the network's payroll department, and their attorney spoke to ABC News' "Good Morning America" on Wednesday about the allegations, which they described as "appalling" and "insulting."
The lawsuit is the latest in a string of allegations of misconduct by current and former staff members stretching back to last summer.
Since then, other allegations made against company executives have beset Fox News.
In the lawsuit filed Tuesday, which is an amended version of a complaint originally filed last week, Tichaona Brown and Tabrese Wright claim that former Fox News Senior Vice President of Accounting Judith Slater ridiculed black employees at the company.
"That was definitely the tipping point for me," Brown told "GMA" in an interview Wednesday. "I want a voice for many years of feeling voiceless."
In the same interview, Wright told "GMA" that Slater called their department the "urban payroll division."
Wright recalled a conversation she had once with Slater in an elevator, where she mentioned that she had three children. Slater allegedly replied: "All by the same man?"
"I was shocked," Wright said.
A third black female employee named as a plaintiff in the lawsuit, Monica Douglas, claimed she "was subjected to the same racially discriminatory treatment experienced by Ms. Brown and Ms. Wright."
In addition, Douglas claims that Slater made fun of her Panamanian heritage and "complained that Ms. Douglas has 'black eyes' as opposed to the 'Aryan race,' who have blue eyes and blond hair."
Douglas said she raised the issues with Fox's general counsel, who allegedly told her that Slater is "untouchable" and "cannot be fired because she knows too much."
"That's really the bigger story here. There really is a cover-up going on at Fox at the highest levels," the women's attorney, Douglas Wigdor, told "GMA" on Wednesday.
"They fired [Slater] knowing for many years that she was engaged in this conduct and that’s reprehensible," Wigdor added. "They let it happen because she was the comptroller and she was privy to all of the information about all the various different settlements that had been going on at Fox for years."
A version of the lawsuit that included only Brown and Wright was filed March 28. Tuesday's filing added Douglas and further allegations.
Responding to the amended complaint, a Fox News spokesperson said in a statement: "We take complaints of this nature very seriously and took prompt and effective remedial action in terminating Judy Slater before Ms. Brown, Ms. Wright and Ms. Douglas sued in court and even before Ms. Wright and Ms. Douglas complained through their lawyer. There is no place for conduct like this at Fox News, which is why Ms. Slater was fired."
A Fox News spokesperson also told ABC News that the network has hired a new head of human resources, and that it fired Slater on Feb. 28, within two weeks of learning about her alleged actions. The new executive vice president of HR, Kevin Lord, was appointed on Dec. 14, according to a company press release.
Attempts by ABC News to reach Slater for comment were not immediately successful Tuesday.
The amended lawsuit comes a day after Fox News contributor Julie Roginsky filed a lawsuit against the network claiming misconduct on the part of Ailes, the company and current co-President Bill Shine.
In her lawsuit filed on Monday, Roginsky claimed that Ailes encouraged her to hook up with "older, married, conservative men," insisted on a kiss as a greeting and made "sexist" comments about female on-air staff.
The suit also claims that Roginsky faced retaliation when she "refused to engage in a sexual relationship with Ailes." She also claims that she suffered retaliation at the hands of Shine, who is now co-President of Fox News. Ailes has denied Roginsky's allegations.
Fox News did not comment on the Roginsky suit.
Carlson ultimately settled her case for a reported $20 million in September.
An investigation published by The New York Times on Saturday reported that five women received settlements from Fox News and one of its hosts, Bill O’Reilly, totaling some $13 million after making misconduct accusations against the top-rated host. Some of these settlements were already known and date back to 2004.
ABC News has not been able to independently verify new information in the Times story. However, as ABC News reported in February, federal prosecutors in New York City are conducting a criminal probe of the news company to determine if any laws or accounting regulations were violated when it paid money to settle misconduct accusations made against Ailes.
Asked about The Times' investigation, 21st Century Fox, Fox News' parent company, said in a statement that it "takes matters of workplace behavior very seriously."
"Notwithstanding the fact that no current or former Fox News employee ever took advantage of the 21st Century Fox hotline to raise a concern about Bill O'Reilly, even anonymously, we have looked into these matters over the last few months and discussed them with Mr. O'Reilly. While he denies the merits of these claims, Mr. O'Reilly has resolved those he regarded as his personal responsibility. Mr. O'Reilly is fully committed to supporting our efforts to improve the environment for all our employees at Fox News," the statement continued.
In a statement posted on his website on April 1, O'Reilly wrote in part: "Just like other prominent and controversial people, I'm vulnerable to lawsuits from individuals who want me to pay them to avoid negative publicity. In my more than 20 years at Fox News Channel, no one has ever filed a complaint about me with the Human Resources Department, even on the anonymous hotline."
He said that the "worst part" of his job was "being a target for those who would harm me and my employer," and his "primary efforts will continue to be to put forth an honest TV program and to protect those close to me."
Since then, however, pressure has mounted on Fox News and O'Reilly.
O'Reilly's namesake show, "The O'Reilly Factor," brings in more revenue than any show on Fox News, or its main competitors CNN and MSNBC, according to Kantar Media, a market research firm. The firm said that the show brought in some $126 million in revenue in 2015.
But as of Tuesday a slew of top brands had pulled advertisements from O'Reilly's program, including Allstate, T. Rowe Price, GlaxoSmithKline, BMW, Mercedes-Benz, Hyundai, Constant Contact, UNTUCKit and Sanofi.
In a statement Fox News said, “We value our partners and are working with them to address their current concerns about 'The O’Reilly Factor.' At this time, the ad buys of those clients have been re-expressed into other FNC programs.”
Meanwhile, the National Organization for Women, a leading feminist organization, has called on Fox News to fire O'Reilly and demanded "an independent investigation into the culture of sexual harassment at Fox News."
ABC News' Devin Villacis, Shahriar Rahmanzadeh and Morgan Winsor contributed to this report.