WASHINGTON — Alex M. Azar II, the secretary of health and human services, said Thursday that doctors and hospitals should tell patients how much their care would cost before patients received treatment. And if they do not do so voluntarily, he said, the government may use its leverage to force them to disclose the information.

Mr. Azar, speaking to a conference of health insurance executives, said that such information would give patients more control over their health care. And that, he said, would advance one of the Trump administration’s top priorities: “the value-based transformation of our entire health care system.”

“You ought to have the right to know what a health care service will cost — and what it will really cost — before you get that service,” Mr. Azar said.

His speech — and similar remarks this week by other federal health officials — amounts to an experiment in jawboning by an administration viscerally opposed to new regulations. It is unclear what President Trump will do if the exhortations fail to produce the desired results. Mr. Azar hinted, at a news briefing on Thursday, that the administration’s policy preferences could be included in Medicare regulations and perhaps, if necessary, in legislative proposals.