Ordering Apple to access data against its will would be akin to making a reluctant drug company carry out a lethal injection, a US judge has said.

Judge James Orenstein was hearing a US government request to make it retrieve information from a locked iPhone seized by law enforcement officers.

On Monday, the judge expressed doubt that he had the authority to do so.

Apple has agreed to similar requests previously but is now refusing, saying it would erode customers' trust.

'Inflammatory'

Referring to the US Department of Justice's request for him to order Apple to help it unlock the phone, the judge said: "What you're asking [Apple] to do is do work for you."

And he compared the request to a hypothetical one in which the government was asking him to order a drug company to take part in an execution against its conscientious objection.

He asked the department's lawyer, Saritha Komatireddy, whether or not he would have the legal authority to do so.

Ms Komatireddy asked to respond in writing, adding that the hypothetical was "somewhat inflammatory".

"Purposefully so," the judge responded