Greymouth / Hokitika would be closer then haast.
I have never fished Haast before but on my recent trip to Greymouth/Hokitika I decided the beach was much to shallow and boring to fish. It was also quite rough when I was down that way.
The beaches around Hokitika/Greymouth and dominatly sand. Although there is rocky stoney coast north of Greymouth.
From my understanding, the coast around Haast are shingle and rocky beaches… I personally feel at this time of year haast would be the more interesting place to prospect. Was planning a trip down that way myself but decided the coast of the accomodation was to much so went to Golden Bay instead.