A 4WD track that takes you along the southern coast of the South Island. We didn't get to drive the entire thing - but it ran for a decent distance and appears that you might be able to get onto the beach in the distance. It's not hard as such but it's tight and has very few turn around areas.
Stick to the public track - don't venture into private land.
This is just a small amount of the information available in Overland Navigator. By creating an account you get access to all the information you need to explore this track and many more.