The technology company made the argument in a brief filed in federal court in the New York City borough of Brooklyn on Friday, a week after the US Department of Justice said it would push forward with its appeal of a federal magistrate's ruling saying he could not force the company to assist authorities.
The government's decision to continue appealing the February ruling at a higher level, to US District Judge Margo Brodie, came after an outside party provided the US Federal Bureau of Investigation a way to access the phone in the San Bernardino case without Apple's help.
In its brief, Apple argued the government had not said if it had tried to use the secret method from the San Bernardino case on the iPhone in the drug case, nor if authorities had consulted with the unnamed third party or anyone else about it.
Apple, which reiterated many of its other legal arguments in the case, said the government "has utterly failed to satisfy its burden to demonstrate that Apple's assistance in this case is necessary."
The Justice Department, in a statement, noted that some 70 times before the Brooklyn case emerged, Apple had helped authorities access data on iPhones.
"Indeed, Apple has said it would take them only a few hours to open this kind of phone, because they already have a mechanism that would allow them to do so," the Justice Department said.
Prosecutors are challenging a Feb. 29 ruling by US Magistrate Judge James Orenstein holding he did not have the authority to order Apple to disable the security of an iPhone seized in a drug probe.
That case has taken a higher profile after prosecutors dropped their effort to get Apple's help accessing the phone of Rizwan Farook, one of the two killers in the San Bernardino massacre, which left 14 people dead and 22 wounded, after a third party provided the FBI a method to crack it.
That phone belonged to Jun Feng, who has pleaded guilty to participation in a methamphetamine distribution conspiracy, which prosecutors are continuing to investigate.
Unlike the phone used in San Bernardino, Feng's phone had an older operating system, iOS 7, which is not protected under the same encryption technology, which is why Apple could access it.
© Thomson Reuters 2016