Members of union Unite plan to display the banner on Wednesday at 11am.
Amazon, which has a giant fulfilment centre at Rugeley, reported that its first quarter profit of £5.8 billion had more than tripled from a year ago, fuelled by the growth of online shopping during the pandemic.
Unite is now calling on chief executive Jeff Bezos to sign up to a declaration of neutrality.
Its executive officer, Sharon Graham, said: “Amazon’s profits have tripled off the backs of workers who have been essential during the pandemic. But the company continues to be plagued by reports of poor working conditions and anti-union tactics.
"Amazon workers are not currently free to join a union without fear, and without obstruction and propaganda being deployed against them.
"Workers have serious concerns about issues such as bullying, mandatory overtime, intense surveillance, break-neck production targets and much more besides. Amazon workers need an independent voice to stand up against injustices in the workplace.
"Unite has recently written to Jeff Bezos in response to claims from the company about respecting UK workers’ rights to join and form a union. Our union is calling on the company to make a clear commitment and sign up to a declaration of neutrality. The declaration would guarantee workers the freedom to talk with and form a union without fear. If the company is genuine then it should be more than happy to sign the declaration."
Amazon issued a response saying: “The fact is we already offer our employees excellent pay, excellent benefits and excellent opportunities for career growth, all while working in a safe, modern work environment.
"Our competitive wages start at £9.70 or £10.80 per hour depending on location, and we’d encourage anyone to compare this to the wages and benefits offered by other retailers.
"We’re proud to have created 10,000 new permanent roles across the UK in 2020, taking our total permanent UK workforce to more than 40,000. Our people have played a critical role in serving customers in these unprecedented times and the new roles help us continue to meet customer demand and support small and medium-sized businesses selling on Amazon."
Unite has launched a confidential whistle-blowing hotline in the UK for Amazon workers on 0800 014 1461.