Tesco has suspended 24 hour opening at some supermarkets with reports customers are grabbing in demand items out of re-stocking trolleys.
Customers were told that stores in Llandudno Junction and Bangor in North Wales were having their opening hours curtailed.
It comes as panic buying due to the coronavirus outbreak was leaving shelves empty.
The move - which has seen the store in Llandudno Junction close at 10pm - is to give staff time to replenish stocks safely and efficiently amid huge stockpiling by customers.
One shopper was told that some customers had been removing in demand items from the stocking trolleys used by staff - disrupting the re-stocking process.
A sign at one store said the decision was for "customer safety" - which is understood to be related to people trying to take goods from the large trolleys.
Staff said the restricted hours in Llandudno Junction would continue this week.
The store in Bangor also closed early on Saturday, and on Monday evening.
Most Read
A source has confirmed that Tesco in Llandudno Junction will open from 6am until 10pm and Tesco in Bangor from 6am until 9pm.
This will continue for a temporary period although no dates were confirmed.
Tesco has been asked to comment.