"Press" keypad buttons during call with voice for DTMF tones

Is there a way to use my voice to "press" a button on the numeric keypad during a phone call?

While some phone systems accept voice input, many still rely upon DTMF tones to be sent through during the call to select certain menu items. Many times, hands are unavailable, and being prompted for keypad input can be frustrating and dangerous.

Is there a way to, for example, have Siri listen to calls for commands like "Siri, press one five one pound", to send the DTMF codes "151#" on behalf of my hands?