The Dutch Gaming Authority (KSA) imposed a €500,000 fine on N1 Interactive for providing gambling to Dutch players without a license.
The Maltese company N1 offers gambling business in the Dutch market through its Betchan brand.
A study by the regulator found that betchan.com was accessed from the Netherlands and there were numerous instances where the site offered offers to Dutch players.
One such example was when the word "Amsterdam" was used as a bonus code for consumers.
The KSA stated that the decision to impose the fine was made not only due to N1's lack of a license and targeting Dutch players, but also due to the lack of a visible age verification process and due to players' accounts being charged for inactivity.
Apart from the fine, betchan.com is no longer available in the Netherlands.
The Dutch gambling market is currently in the process of regulation and potential operators can now apply for a license to offer gambling in the country.
The new regulated market is due to open on 1 October.
René Jansen, Chairman of the KSA, said: “All conditions are aimed at ensuring that a safe legal proposal is in place as soon as possible, thanks to which players will be assured of fair play and will be protected from gambling addiction.
“This includes a strict approach to illegal shipments now and after October 1st,” he added.