Do most hotels in Auckland allow you to drop your luggage if you have a reservation?

I arrive in Auckland at 6:30 am, which means that I will probably have a few hours before the hotel I decide to stay in lets me check in. I kind of like to use the hotel as a stable base especially when travelling overseas, but even though I am expecting not to be able to check in, will most hotels let you leave your luggage, so then you can go on and sightsee? Also, is it better to reserve online, at least my first night of lodging, or wait and find a room when I get there, I would think beforehand for a better piece of mind, but I just want to make sure in case someone has some other information that I may not be made aware of. Thanks for all the input.