It will offer more seamless travel between the two carriers with passengers able to transfer frequent flyer miles, baggage allowances and lounge access.
Combined, there will be almost 130 return flights a week between New Zealand and Australia, and then on to more than 65 destinations across Europe, Asia North, Africa and the Middle East on the joint network alone.
Commercial director of House of Travel Brent Thomas said the reach for travellers to and from New Zealand would increase.
"It does make it easier for travellers between the two carriers and anything that makes it easier for the customers, as long as there's competition, is going to be good."
The airlines want to ensure their flights don't depart or arrive at the same time, which may require some rescheduling.
The alliance will allow Emirates to offer Queenstown and Wellington as destinations on codeshare flights with Qantas. Neither airport is able to handle the Boeing 777s and A380s that Emirates operates but Qantas and its subsidiary Jetstar serves them with Airbus A320s and Boeing 737s.