Passengers with low-cost airline Ryanair will no longer be able to take a 10-kilogram piece of hand luggage on board for free under a new policy introduced on Thursday.

Under the new rules, passengers who want to bring anything bigger than a "small personal bag" will be charged extra unless they are a priority boarding customer.

Priority boarding costs 6 euros (7 dollars). Customers who do not choose priority boarding will have to pay 10 euros for an extra piece of cabin baggage.

The new policy has provoked outrage on social media, with some customers claiming they will never fly with Ryanair again.

The budget airline has had a difficult year plagued by strike action across Europe. Last month, it reported a 7-per-cent fall in profits in the first half of its financial year, blaming "widespread damage" from the strikes, among other things.

Ryanair also came under heavy criticism last month for its lacklustre response to a passenger who launched a racist rant at the woman sitting next to him, after a video showing the incident was circulated on social media.