The 46-year-old believes that Samoa will top the nation's group - which also contains South Africa, Namibia and Fuiji - in the tournament that begins in his homeland in September.
"I think Samoa will be the real outsiders in New Zealand. The Pacific islands of Fiji, Samoa and Tonga will all be tough but it is Samoa that stand out," he told Sky Sports News.
"In my opinion Wales will not get into the knockout stages and at the moment South Africa still have work to do, so I just have this feeling that Samoa might top the pool."
Brooke played in three World Cups between 1987 and 1995 for the All Blacks.