Online ticket agencies that bump up the price of concert and festival tickets with hidden surcharges will face fines from October following a ruling from the Dutch competition authority ACM.

The ACM responded to complaints from customers who were hit with extra costs that added up to 20% to the cover price.

Agencies have been given until October 1 to update their terms and conditions so that all charges are clearly specified before the customer clicks through to the booking. Those that fail to comply risk a fine.

The move mirrors similar regulations to cover the sale of airline tickets, holidays and cars online. In 2015 online travel agency Corendon was hit with a €350 million fine for two breaches of the rules, though the company is appealing against the decision.