Amazon will keep its six warehouses in France closed until at least April 22 after a stand-off with unions over sanitary conditions amid the coronavirus outbreak, it said on Sunday. The Seattle-based e-commerce giant has been under scrutiny over its working practices on both sides of the Atlantic since the start of the pandemic, with workers raising concerns over the risks of contagion while fielding shipments.

US unions and elected officials have called on Amazon to close down buildings while in France worker representatives took the firm to court, saying its health protocols were not good enough.

A French court last week ordered Amazon to restrict its deliveries to bare essentials such as groceries and medical supplies while it makes thorough safety checks.

But Amazon went further and suspended activity at six so-called fulfilment centres where it processes and packs items, in one of the biggest fallouts from the backlash yet.

It said that the definition of essential goods was not clear and it could not risk being fined, and has lodged a court appeal now due on April 21

"We're waiting with interest for our appeal to be heard," the company said, adding that warehouse employees would have to stay at home until at least April 22. Amazon had previously said the closures would apply until at least April 20.

The US firm has encouraged shoppers to keep ordering, and taken out advertisements in French newspapers saying vendors that use Amazon's site to showcase their wares but have their own logistics would still be able to deliver.

In addition, the company has said it will try to minimise disruptions by using other warehouses in Europe to fulfil orders, though some shoppers said they had already been warned of delays of up to four weeks to receive their goods.

France is under virtual lockdown to contain the virus outbreak and most stores except for supermarkets are closed.

The Amazon dispute comes as the government tries to strike a balancing act, ensuring companies are bringing in sanitary precautions while avoiding a total economic shutdown.

Amazon has said its health guidelines are adequate, adding it has provided staff with face masks.

Unions have argued that social distancing is hard to respect in busy warehouses, and want the company to cut back on the number of products it is delivering during the crisis.