The British company, which sells its clothing and homeware ranges through its website and app, said it made the decision as part of "proactive management" of the incident.
"Our experienced team - supported by leading cyber experts - is working extremely hard to restart online and app shopping," the company said on X, apologising for the inconvenience and stating that its stores remained open.
Some M&S International operated websites were also pausing orders, it said.
M&S is a fixture in most British towns, and it posted revenue of about 13 billion pounds last year from its upmarket food as well as clothing, homeware and beauty. About one third of its clothing and home sales are online.
It said on Tuesday it had been affected by a cyber incident and was making some temporary changes to store operations as a result.
In recent days customers told the BBC they been unable to make contactless payments and some click and collect orders had been delayed.
The National Crime Agency said it was aware of the incident and its officers were working alongside the National Cyber Security Centre to support the company.
