You need to declare fishing equipment when entering NZ, not sure about the other way. Probably do.
As has been mentioned, make sure it's clean - particularly no sign of any seaweed or crustaceans - and relatively accessible if it's in checked in luggage.
Don't try to take sharp objects such as hooks, lures or, goes without saying, knives in your carry on.
Also, remember that in NSW you need to buy a recreational fishing licence for salt water fishing - certainly with a rod and line, not sure about nets. Probably do. Ignorance isn't a defence, so read up the regulations on line.