The ruling was issued as part of a criminal case against Jun Feng, who pleaded guilty in October to drug charges.
This could boost Apple's resistance to the US government's similar effort in the case of the San Bernardino killers, according to analysts.
US Drug Enforcement Authority seized Feng's IPhone 5 but could not access it even after consultation with the FBI.
The government then filed a suit against Apple seeking a court motion to order "Apple to assist" the investigation “under the authority of the All Writs Act” by “helping the government bypass the passcode security."
Apple objected, saying that there were nine other cases currently pending in which the government was seeking a similar order.
Department of Justice officials expressed disappointment, saying they will ask a judge in a superior post to Orenstein to review his ruling in coming days, the LA Times said.
“This phone may contain evidence that will assist us in an active criminal investigation and we will continue to use the judicial system in our attempt to obtain it,” the department said in a statement.