Throughout his career, Brewer has represented Canada at various international ice hockey tournaments. He first competed internationally as a member of Team Pacific Canada at the 1995 World U-17 Hockey Challenge in Moncton, New Brunswick. Three years later, he represented Canada as a whole as a member of the national junior team at the 1998 World Junior Ice Hockey Championships, where he was named an alternate captain. This was the tournament in which Canada had its worst ever showing, an eighth-place finish including a loss to Kazakhstan, giving Brewer an unkind welcome to IIHF international ice hockey. Although eligible for the 1999 edition of the same tournament, Brewer was unable to play due to NHL commitments with the New York Islanders.