Union bosses say they are "appalled" at claims by JD Sports staff that the company is ignoring safety concerns over coronavirus.
Workers have complained to the shopworkers' union Usdaw about a lack of social distancing and hand sanitiser at the firm's warehouse in Rochdale.
Greater Manchester Mayor Andy Burnham called for "a stronger policy on workplaces" after 1,000 complaints.
JD Sports said the "health, safety and wellbeing" of its staff was a priority.
Mr Burnham said: "It's not about shutting people down if they can practise the safe distancing rules properly.
"This is simply about keeping people safe, public health has got to come first."
Social distancing guidelines aimed at preventing the transmission of coronavirus mean people must stay more than 2m (6ft) apart from others.
But one worker at the JD Sports warehouse in Rochdale told the BBC that was "not possible".
He said: "We have to work side-by-side and people are going to be in danger.
"Let's just shut it down for a few weeks, let this thing subside, we will save lives, we will save our people, all our colleagues and our friends."
Tony Clare from Usdaw said he was "appalled but not surprised" at members' complaints about a lack of coronavirus safety in the workplace.
He said: "They also tell us there's a complete lack of compassion for anyone personally affected by the coronavirus and who may need to take time away from work."
But a spokesman for JD Sports said: "We have increased hygiene and cleaning processes, and have implemented social distancing measures in our distribution centres, in order to minimise any transfer risk at our facilities.
"We have dramatically reduced the number of colleagues on site and will continue to act in line with the latest government advice."