I am a NZ 14 or about a US 10 in trousers. I read the reviews and got the 12, so glad I did. Close but good fit. Slim in the legs on me, but still comfortable getting in and out of our small boat! Would recommend. I am 5'5 (165cm tall) 70kilos (11 stone) - slightly strong but not fat build.
I would have liked the waist band to be elasticated like in the mens, rather than the tie & velcro, but they do stay put.