UPDATE

As Jordi pointed out in the comments. If you enable Siri, then Voice dialing option will be available. For more information see the link that Jordi sent https://discussions.apple.com/message/25141341#25141341.

OLDER UPDATE

iPhone 5s seems to be unaffected. Also according to a comment I received the problem may just be both ways, he cant turn it on. But still its a nuisance.

Old article

So I have always liked being on the cutting edge in software. It helps as when my customers ask me things I have already hit that myself. But this time it hit me harder than usual.

One thing I have hated with IOS is the voice dialing and that it gets turned back after each update. But I do the regular thing and disable it. But this time things had changed.. I could no longer find it. Nor the menu where it was, well Apple had made it more accessible, Passcode lock is now placed directly under General instead of General\Settings. But instead they have removed option to disable Voice Dial.

Screen by screen of IOS 7 and 7.1. Password lock screen missing Voice dial in 7.1.

This might be the final thing that forces me to leave iPhone. I have had problems with pocket calling, but disabling voice dial solves it. Without it I feel forced to switch.

I have verified with an iPhone 5S that they can disable Voice Dial.