A Coles spokeswoman confirmed the outage, but said customers had been offered compensation.
"Our team is working to get the site back online and we apologise to our customers for the inconvenience," she told 7NEWS.com.au.
"As a gesture of goodwill, we have offered affected customers with flybuys accounts impacted by the outage a $15 credit to spend in-store."
It remains unclear when the site will be restored.
This content originally appeared on 7NEWS.com.au