Found this one after the targetted 20 off 120 didn't work for me. This doesn't appear to be targetted which is nice.
From the news.com.au site: "Get groceries delivered straight to your home or pick it up at a store near you for a fraction of the price with this Woolworth coupon code! Shop now and take $20 off any $200 spend!"
Incidentally, the "fraction of the price" is 9/10ths if you spend exactly $200.
Edit: There's also a 10 off 100 offer on the same linked page if that suits you better.