An ongoing Coles website outage has caused pandemonium among shoppers relying on the supermarket’s online grocery delivery service.

The Coles Online website has been down since Sunday, with the retailer telling customers to instead use its eBay store or head to their nearest supermarket.

On Tuesday afternoon, a Coles spokesperson told The New Daily the website was offline “due to an internal software issue that occurred during regular maintenance”.

“Our team is working to get the site back online and we apologise to our customers for the inconvenience,” the spokesperson said.

The reassurances did little to comfort some affected customers, who took to social media to voice their frustration.

“Can you please update everyone on an approximate fix time? I’m trying to run a business and it’s super frustrating!” Facebook user Angi Fullwood wrote.

The outage also prompted concerns for shoppers with disabilities and chronic illnesses who rely on the online delivery service.

“Does this mean we get free delivery? I normally get my shopping today and can’t and as I’m visually impaired it is hard to go and get my shopping,” Justin Coull wrote on Facebook.

Coles’ social media team told Mr Coull that it was “unable to advise on any compensation for the down time”.

The New Daily asked Coles what it was doing to accommodate disabled and chronically ill customers who rely on the website for their shopping needs, but did not receive a response.

The outage comes just a month after Coles revealed it would try to capitalise on Australia’s growing online grocery shopping market through a $150 million deal with British online supermarket Ocado.

Under the deal, Coles will seek to double its home delivery services within the next four years.

On Monday, Coles revealed that it had boosted its third-quarter food and liquor sales by 2.1 per cent to $8 billion on the back of another successful collectables promotion.

The supermarket giant said its Fresh Stikeez campaign “drove high customer engagement” in the 12 weeks to March 24, mirroring the runaway success of last year’s Little Shop giveaways.