Forbes reported that the workers were staging protests in order to draw attention to what they claim are bad treatment of low-level employees who have been critical of the company's working conditions.
In Australia, the activist group SumOfUs urged the public to donate sums ranging from $4 to $8 and fund ads against Amazon's employee policies.
"With your donation we’re going to plaster the Internet with anti-Amazon ads on Amazon Prime Day. Every time a shopper sees Amazon advertising new deals, your ad will be sitting right alongside - telling customers everything they need to know about Amazon’s shocking mistreatment of workers," a SumOfUs spokesperson said in a statement.
In the run-up to the Prime Day, Amazon workers in Spain went on a strike last week. Other centres, in France, England, Germany and Poland, are reportedly set to stage similar protests.
The Australian SumOfUs spokesperson said: "Amazon exploits and underpays its warehouse workers and same-day delivery workers all over the world – but with your help, we have an opportunity to usurp the messaging on Prime Day to focus on the human cost to all these discounts."
In a statement sent to iTWire, an Amazon spokesperson did not directly address the protests or the claim that employees had to urinate in buckets but said: "Amazon is a fair and responsible employer and as such we are committed to dialogue, which is an inseparable part of our culture. We are committed to ensuring a fair co-operation with all our employees, including positive working conditions and a caring and inclusive environment.
"Amazon has invested over €15 billion across Europe and have created over 65,000 permanent jobs since 2010 and provides a safe and positive workplace with competitive pay and benefits from day one. We encourage anyone to come see for themselves by taking a tour at one of our fulfilment centres."