State correctional institutions are seeing COVID-19 spread within their walls, the governor said, leading him to sign the order.
People convicted of what Murphy called serious crimes like murder or rape would not be eligible for home confinement or parole.
New Jersey's death toll from COVID-19 climbed by 233 people to about 2,000 on Friday, Murphy said.
The number of positive cases in the state reached about 55,000, up 3,600 over the previous 24 hours, Murphy said.
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