The KSA has imposed an order subject to periodic penalty payments on Postcode Loterij and VriendenLoterij for offering online games that are not permitted according to their lottery licences.
The two lottery operators said they will appeal the decision but will temporarily stop offering the games from 8 June.
The regulator said the operators would be liable to pay a penalty of €250,000 per week, up to a maximum of €1m, should they offer the games again.
KSA deems lottery to be offering games of chance.
KSA said the lottery licence does not cover titles such as Deal or no Deal, offered by Postcode Loterij, and FriendsLottery Millionaires, which it deems to be online games of chance.
“Legislation and regulations make a clear distinction between lotteries and more risky games of chance, including online games of chance,” the KSA said in a statement.
“A different licence is required for both games of chance.
“Lotteries may not be offered online; it is only permitted to sell participation tickets via the internet. The online offering of games that are linked to a lottery is prohibited. The law does not allow this. The KSA remains keen to ensure that lottery and online games of chance remain separate.”
In response, Postcode Loterij and VriendenLoterij said it would appeal the decision.
In a joint statement, they added: “The KSA is of the opinion that these free lottery games do not fit within the lottery licence. However, the games are a form of entertainment and fit within the safe nature of a non-profit lottery with only one goal: to raise funds for good causes.
“For the past 30 years, participants have always been able to participate in additional games in this way, whether or not via the mail, the internet, in special apps or live.
“Nothing is won by playing one of the games itself. In the games, like a traditional lottery, participants only receive a prize after a draw has taken place. With this, the games meet the requirements of the lottery licence.”
Last week, a report published by Marnix van Rij, the Dutch finance minister said the government is “exploring” new options for Nederlandse Loterij (NLO), including the possibility of privatising the state-owned enterprise.