Morrisons, Iceland, Sainsbury’s and Aldi are to install thousands of protective screens at checkouts to keep staff safe as concerns grow about their wellbeing while dealing with hundreds of customers a day during the coronavirus outbreak.

Several retailers have asked shoppers to keep at least a metre (3ft) away from staff at tills, but some shop workers have said on social media that they have not been allowed to wear protection such as masks.

The general secretary of the shop workers’ union Usdaw, Paddy Lillis, said: “We have increasing concerns about the safety and welfare of staff in stores. The scenes in stores over the weekend and behaviour of some customers mean that supermarkets need to go further to protect the health, safety and welfare of shop workers.”

Supermarkets and their staff have come under massive pressure as shoppers have stockpiled goods and switched from dining out to cooking at home.

The average spend per supermarket trip rose by 16% in the week ending 17 March. In the same period, there were an additional 15m food shopping trips – an increase of 12% – according to the market analysts Kantar, amid widespread concern about shortages of essentials.

There has also been heavy demand for home deliveries, putting extra pressure on staff in store who pick many of those orders. In response to the surge, Marks & Spencer is teaming up with the takeaway firm Deliveroo to offer 60 goods, including milk, cereal and ready meals, for delivery within 30 minutes. The tie-up, using 120 M&S franchise stores based on BP petrol forecourts, will offer deliveries in Reading, Brighton, Nottingham, Manchester, Leeds and London over the next two weeks.

Some retailers said they had struggled to obtain enough protective equipment for staff in stores because suppliers were understandably prioritising the NHS. More than 3,000 supermarket workers have signed a petition on employee campaigning platform Organise calling for masks and gloves to be supplied.

Lillis said: “We are calling on retailers to continue to improve their stores and procedures to help protect staff.”

The union welcomed the new measures being taken by supermarkets but said it wanted retailers to protect staff further with measures including:

• Limiting the number of customers in store at any one time.

• Increasing security.

• Telling customers to shop alone if possible and only buy what they need.

• Enforcing essential workers’ and vulnerable people’s shopping hours.

Morrisons’ chief executive, David Potts, said the company had employed 83 fitting teams to install protective screens at every checkout as soon as possible. “The wellbeing of colleagues is paramount,” he said. It has also put hand sanitiser on all tills and marked out physical distancing points on store floors.

Tesco, Sainsbury’s and Asda are understood to be reviewing measures to protect staff, such as potentially limiting the number of shoppers in stores at one time, but have not provided workers with masks.

Tesco said it had introduced physical distancing measures, such as lines on the floor, around checkouts and queue barriers in large stores.

Sainsbury’s said it would now be asking customers to stand two metres away from each other and staff wherever possible and pay by card rather than cash at the tills. It will start installing acrylic screens at the end of this week.

Sainsbury’s is also handing hourly paid staff in its supermarkets, Argos chain, delivery network and customer contact centres a one-off 10% increase in hourly pay between 9 March and 5 April. Sainsbury’s said the payment was in recognition of “going above and beyond to serve customers during this challenging time”.

Asda has provided staff with gloves and hand sanitiser. It said it had also extended breaks so that employees could wash their hands more frequently and asked customers to pay by card whenever possible.

One Tesco worker said: “A lot of workers don’t feel comfortable. They are trying to protect their workers, but there’s not enough gloves and masks. Everyone’s pretty responsible, a lot of people obviously concerned. Everyone has got a granny at home or young kids.”