I came from Reefton and spent most of my life around Greymouth.
For you younger fossickers there are some good easy places to get to that are not so well-known. Especially in the Hokitika area.
Blue Spur/Mt. Mckay: just outside of the town all the creeks flowing from there have good colour in them. Especially the back road to Goldsborough. be careful of old mineshafts there!! Houhou Creek is good as well.
Woodstock: just inland from Hokitika, the creeks are good and easy to get to. If you're lucky you will get some small rubies there as well!
Lake Kaniere Rd: Coal Creek has gold in the banks about half way between the town and the lake. Bluebottle Creek, Mackay's Creek, Johnson's Creek has some too.
Those are some places to have a scratch around in.
Get yourself a good map of the West Coast and draw a line from Garvey's Creek, Reefton to Mt. Greenland, Ross. Every creek or river that crosses that line is gold bearing. Gold to the west, barren to the east of it. It was where the old glaciers terminated!