Looks like it's a done deal. Always was I guess, well before "submissions", see this:

Driving age set to rise - politics - national | Stuff.co.nz

I see they're using the word "likely" (yeah, right!) And still not saying what the "raised age" is to be.

One thing is for absolute sure, we cannot ever rely on the word of a minister of the crown (particularly the minister of transport). Ministers of transport in the National party - well any party for that matter - have had a consistent record of "lying like flatfish". So where it says "Public submissions on a review of road safety showed most people supported raising the driving age", we can know for certain that Steven Joyce's nose is growing as he says it.

When I made my "submission" I talked to others and nobody supported this lunatic idea. I even listened to talkback radio programmes about it and - unusual for talkback as they usually get the "hang them, crush their cars, raise the driving age to 90" brigade - people generally didn't see any merit in Steven Joyces insistence that the driving age be raised.

I think he is really talking about a poll he took on this subject with only bureaucrats from the ministry offices participating.