In New Zealand 'up' often means north, and 'down' south, but it also, depending on where you are, refers to altitude. I'm currently at 550m elevation, and I'd go down to the coast even though the place I'd probably go to is very slightly north of here.

The area I'm in is often referred to as the 'High Country' so that probably explains the up and down idea. I'd still go 'up' to Auckland because it's north, even though it's at sea level.