The Danish Maritime Authority can detain a Danish ship if it does not have the right certificates, if the health and safety of the crew is jeopardised, or if there is a risk of pollution of the sea.
Information about Danish ships that have been detained by the Danish Maritime Authority as well as about the shipowners that are responsible for the safety is available here (when a ship is released, it will be removed from the list):
Flag States have the right to control foreign ships in their ports to see whether all regulations are met. If that is not the case, the ship can be detained until the defects have been remedied.
Additional information about port State control and quality shipping:
Paris MoU (Europe and the North Atlantic)
Overview of detained ships
The flag States have concluded a cooperation agreement on common control systems - the so-called Memoranda of Understanding (MoU). Denmark takes part in the cooperation under Paris MoU.
The Danish Maritime Authority inspects at least 25 per cent of foreign ships calling at Danish ports annually.