Sainsbury’s has said it is experiencing “technical issues” at some stores meaning it will not be able to fulfil the “vast majority” of online grocery deliveries.

The supermarket chain said on Saturday morning it was “working hard to fix the issue” and apologised to customers affected.

There have been problems with contactless payments due to an error with an overnight software update, although all stores were open as usual and chip and pin and cash transactions were working, a spokesperson told the PA news agency.

A statement said: “We’re experiencing technical issues affecting some stores, our Groceries Online service and our ability to contact customers.

“Unfortunately, we will not be able to fulfil the vast majority of today’s Groceries Online deliveries.

“We are working hard to fix the issue and apologise to our customers for the inconvenience.

“We will contact customers proactively to rebook orders as soon as we can.”

One customer said she was meant to have a “very important” order delivered between 8-9am, which did not happen.

Yvonne, 56, from the Reading area, said: “The main issue I have with this is the poor communication from Sainsbury’s to its customers.

“It was obvious something was wrong at 7am as that’s when they send the receipts normally.

“Couldn’t get through to anyone about my 8 to 9 delivery.

“No statement until about 8.30, only seemed to be on social media which not all customers will have.

“Should have been an email or text to customers which would have helped those like myself expecting an early morning delivery. Much to improve on with their communications.”

Argos, which is owned by Sainsbury’s, has also been affected by the software update, meaning customers may have issues with ordering new items or collecting orders in-store.

It said there may be delays in fulfilling orders placed on Saturday.