Punakaiki
About half way between Westport and Greymouth is the township of Punakaiki, although not much there (pub, cafe, camping ground, a few houses, backpackers and a visitors centre) it is a nice spot to hangout for a day or two.
The main attraction is the Pancake Rocks named as they look like stacks of pancakes, these rocks can be quite impressive at high tide and if the seas are rough, the rocks trap water then squirt it out high into the air. There are also lots short walks in the surrounding Paparoa National the Inland Pack Track is the main track in the National Park and is well worth the walk.