According to a New York Times report, Amazon has a demanding and degrading environment.
Employees are forced to respond to emails after midnight. If they don't, they receive text messages demanding a swift response.
Employees suffering from personal crises, including miscarriages and cancer were edged out by the company.
Amazon's boss Jeff Bezos wrote in a memo to staff that the "article doesn't describe the Amazon I know".
"Nearly every person I worked with, I saw cry at their desk," New York Times article quoted one former employee as saying.
The report included testimonials from 100 current and former employees who depict a "bruising" workplace at Amazon, where employees are expected to "toil long and late".
A press representative for Amazon said: "While we generally do not comment on individual news stories, we quickly saw current Amazon employees react."
The abusive work culture report has also been denied by Nick Ciubotariu, head of infrastructure development, Amazon.com Search Experience
Ciubotariu wrote: "No one tells me to work nights. No one makes me answer emails at night. No one texts me to ask me why emails aren't answered."
Bezos also encouraged Amazon employees to read the article, and email him directly if they recognised any of the "shockingly callous management practices.
Bezos pointed out that the company depicted in the article could not survive in the "highly competitive tech hiring market".