In a letter signed by the Hauliers' Chamber Koper branch of the Chamber of Trade Crafts and Small Business (OZS), the hauliers urged the Commission to investigate the matter.

They claim the five-euro fee puts them in an unequal position compared to hauliers serving neighbouring ports, while port manager Luka Koper is abusing its monopoly position.

Luka Koper told the STA that the fee is levied to collect funds for the maintenance of roads and cargo handling surface on the port premises.

It also rejected the hauliers' claim that there is no legal basis for the fee, arguing that the Infrastructure Ministry had confirmed such a legal basis exists in 2006.

As for the assertion that Koper is the only EU port with such a charge, Luka Koper noted that Rijeka in neighbouring Croatia has a similar fee system.

The charge for entering the port has been a long-standing qualm for hauliers and its abolition featured as one of the demands in a mid-2013 protest by hauliers.