Using the link you provided, I've installed the app onto my Samsung Galaxy S4 but hit a problem when I tried to install the New Zealand 2014 maps. These maps from the OpenStreetMaps and the download has failed twice and now appears to be stuck during the third download.
I've used OpenStreetMaps maps before to refresh the maps on my wife's Garmin gps device. So, I'm not sure if I've just been unlucky with the download or there's a bigger problem with the app.
If you're looking for a tool to help you with journey planning in New Zealand then I suggest you look as WAZE.
Even before I moved to NZ from the UK, I've used WAZE as apart from the data plan required to refresh the maps its free and also provides real time traffic information. The company has been recently purchased by Google and incorporated into their Google Maps offering.
As it needs a healthy supply of data for the real time information then you'll need to have a decent data plan but I've found to really useful on my regular commutes into the CBD.