Hi, First off, I moved your post into a new thread, as it wasn't related to the thread you posted in.
Secondly, How are you currently opening the gate? I've seen (movies) people use a garage door fob or using a pincode lock on the side.
I think it's safe to say that the gate installers won't get you a nfc enabled access point unless they have such a service/device readily available to them, Which means that you'll either have to find a service that does or roll your own.
If you haven't already- which should have been your first step, give them a call and see if they provide alternative ways of opening the gates.