Hours later, at a media briefing, Mr. Murphy laid out four broad metrics that will be used to determine when and how businesses can begin to reopen.

He said the approach required success on several fronts: a 14-day decline in new coronavirus cases and hospitalization rates; expanded testing; a robust ability to trace people who have had contact with those infected with the virus; and an increased availability of places, such as hotels, where the sick can remain in isolation, free of charge.

“A plan that is needlessly rushed,” he said, “will needlessly fail.”

When pressed on the timing of a phased-in reopening, he was noncommittal, but suggested it could come by Memorial Day, the unofficial start to summer at the Jersey Shore.

“I want to see the shore humming throughout the summer,” he said.

Still, social distancing is likely to be the norm for months to come, including on beaches, he said.

He said a commission whose members would be announced on Tuesday will be responsible for guiding decision-making. The reopening, he cautioned, would not necessarily mirror the slow wave of shutdowns that began in mid-March.