Community Development, Youth and Sports Minister Vivian Balakrishnan declined, however, to comment on action that may be taken as he could not speak on behalf of the Casino Regulatory Authority, which comes under the Home Affairs Ministry.
CRA on Friday ordered the city-state's two casino operators, Las Vegas Sands and Genting Singapore, a unit of Malaysia's Genting Bhd, to stop providing free buses from residential districts to the casinos with immediate effect.
The order came a day after Balakrishnan's ministry said it was investigating the free shuttle services. He said the casino operators were only allowed to pick up people from specific tourist-linked destinations in the city.
"This signal is to reinforce the point that they are not supposed to go after the low-hanging fruit which the local market represents, but instead to focus their effort on winning additional tourists from abroad," Balakrishnan said.
"I can't speak for the Casino Regulatory Authority whether they are contemplating any penalties to be imposed. There is a due process. They will make appropriate decisions at the regulatory level."
The two casinos opened earlier this year and visits by local residents have crossed the one million mark, Balakrishnan said.
"CRA has reminded the IR (integrated resort) operators that they must comply strictly with our rules against casino advertising to locals. CRA will tighten these rules as necessary in the light of experience," Balakrishnan added.
A CRA spokeswoman said she could not immediately comment on the minister's remarks.
Las Vegas Sands has said that about one-third of the visitors to its Singapore casino are local. The proportion is probably higher at Genting's Resorts World Sentosa, according to analysts and regular visitors.