It seems that most political parties in Cyprus are supporting more and more the use of veto. Also as the climate in Europe has changed, EU countries would be more understanding to the us of veto.
In any case, and altough Cyprus supports Turkey's EU bid, this is a matter of principle. So Cyprus would be forced to exercise veto power for a country that says it doesn't even recognize it even though it wants to be its partner.
So I foresee that Cyprus will exercise veto if Turkey continues its current policy. Lets not forget the huge human rights issues which by themselves, e.g. if Turkey continues to deny personal property from GC refugees is a reason for veto by itself.