But transportation and health officials said they would not prioritize the law, either.

Pedro Peters, the chairman of the Dutch Public Transport Association, told the Dutch news site NU.nl that just as the police would not see someone wearing a burqa or niqab as a top priority, transportation officials consider the movement of buses and trains to be their primary mission.

“You’re not going to shut down the bus for half an hour for someone who’s wearing a burqa,” he said. “We aren’t allowed to refuse anyone, because we have a transport obligation.”

Similarly, the Dutch Federation of University Medical Centers said that it would defer any enforcement to the police, according to The Associated Press. “We are not aware of any cases in which wearing face-covering clothing or a possible ban has led to problems,” its statement said.

In the confusion about who would enforce the law, the newspaper Algemeen Dagblad published an article this week suggesting that any Dutch person could make a citizen’s arrest. The police guidelines confirmed that a citizen’s arrest was possible, but urged people to be cautious.

“That was of course a very welcome signal to some of the right-wing politicians in this country who have sponsored this legislation,” said Tom Zwart, a professor of government at the University of Utrecht. “And for some people on social media, that’s an open invitation to start making life difficult for Muslim women.”

Of the Netherlands’ 17 million people, only about 150 to 400 women wear burqas and niqabs, according to Annelies Moors, a professor of sociology at the University of Amsterdam who studied the potential effect of the ban before it passed. She said that about 5 percent of the adult population was Muslim.

“The law provides a solution for a nonexistent problem, but may in turn cause problems,” she said.

The professor of government, Mr. Zwart, said that for women who wear burqas and niqabs, “it’s not symbolic at all, especially when a newspaper says citizens can make arrests,” he said. “Their safety is at stake.”