Stewart Maxwell, an SNP member for the West of Scotland, said the high-tech tills were not in use when the 2005 Licensing Act came into force and so are not covered by the legislation.
He is urging retailers to suspend the sale of alcohol at self-scanning checkouts to avoid the potential for under-age sales.
Maxwell said: “When you have one person supervising sometimes eight or more tills it is ridiculous to expect them to be taking the same amount of care and attention over a person’s age as they would on an individual till. There is far less contact with the customer and far less chance to assess a person’s age.
“With the increasing use of self-service tills this is an area of licensing law we should look at. It would make much more sense for alcohol to only be for sale through a full service till where a sales assistant can properly assess a customer’s age.”