The Danish pilots union has written to the country's maritime authority to demand compulsory pilotage after a double grounding last month.
In his letter, Lars Sigvardt, chairman of Danish Pilots, wrote: "We complain that the Danish Maritime Authority (DMA) has not utilised a legal basis in the Pilot Act to introduce pilotage for the navigation of ships that have been due on Danish maritime territory."
The Fyns Amts Avis newspaper cited him as saying: "Danish Pilots does not find that the management and implementation of the Pilot Act puts the public's interests first."
The DMA said it would deal with the complaint as soon as possible.
It has the power to make decisions on pilotage based on public safety, military concerns, safety of navigation or environmental issues.
The union said a pilot should have been on board in the case of the 3,000-dwt Rix Amethyst (built 1999), which first got into difficulty as it left Rudkoping.
The vessel had arrived in the port and then loaded 2,800 tonnes of grain destined for the German beer industry in Bremen.
But as it left, the Cyprus-flagged vessel ended up grounding in waters off the North Basin at the port.
The ship could not free itself, so a tug was brought in.
It was refloated after one and a half hours, but was soon in trouble again, grounding a few ship lengths further north near the marina.
After half an hour it was freed under its own power.
Operator Baltic Shipping Company said at the time it was waiting to assess damage.
The company did not respond to TradeWinds' request for further information.
The vessel is classed by RINA and has a clean port state control inspection record going back to 2011.
