The 100ml liquid restriction for plane carry-on baggage is being reintroduced across the EU from next month due to a "temporary technical issue".

A number of airports, including Shannon and Knock, had installed new scanners which meant people could take larger liquids through security in their hand luggage.

Now, however, the European Commission is re-enforcing the restriction at all airports across the bloc due to a technical issue with the new scanners.

In a statement, it said the "temporary restrictions" are needed because the new C3 scanners are having difficulty with larger items.

As a result, the maximum allowed size for individual liquid containers "will revert to the standard 100ml for airports operating this type of equipment".

It said it's working closely with member states to develop "swift technical solutions".

There has been no timeline set to lift the restriction.

Travel Extra editor Eoghan Corry told Newstalk Breakfast the 100ml rule was never actually scrapped.

"What had happened was a lot of airports had got regulatory approval that people would keep liquids in their bags because they got these fantastic new C3 scanners," he said.

"Examples would be found in Kerry, Donegal, Knock and Shannon.

"All people going through security there are allowed to keep their laptops and their liquids in the bag.

"What's going to change on September 1st is the regulation - you can't keep your full 100ml bottle of wine or olive oil in the bag.

"It cannot be liquid of more than 100ml."

A security officer holding a tray of liquids and keys in Cork in June 2016. Picture by: Wavebreakmedia Ltd UC24 / Alamy

Eoghan said the changes are very confusing.

"Laptops can stay in there and if you've got more than one container with 100ml you can keep two, three four of them in your bag," he said.

"The reason is the EU is not happy that the scanners are able to read larger liquid containers correctly.

"The biggest problems are arising not with 75cl [containers] but with the big two litre soft drink containers that everybody's familiar with".

Eoghan said the new scanners were also brought into use 'unevenly' across the EU.

"Some countries were quick in bringing them in others were not," he said.

"Even if you were going to Shannon Airport and you were bringing your liquid it wasn't clear at the hub airport [whether] you'd have to take it out.

"The position in Dublin Airport - by far our biggest airport - is that nothing will change until October 2025.

"Even though they've a few of the scanners they won't have all of them in until October 2025".

Eoghan said the changes means people should stick to current liquid restrictions.

"Stay exactly with what you've been doing, that simplifies it," he added.

Airports that already limit liquids to 100ml or that have not deployed the new scanning equipment are not affected by the change.

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Main image: An airport security check before a flight in September 2021. Image: Jaromír Chalabala / Alamy Stock Photo