Kempson was selected to represent South Africa at various youth or development levels; in 1994, he represented the South Africa Under-23 team and later in the same year, he toured with a South Africa Development side to the United Kingdom. He was named on the bench for in a match in 1995 against in Johannesburg, but failed to make an appearance; but his good form continued as he was named the South African Rugby Young Player of the Year for 1995 In 1996, he played for a South Africa 'A' team that toured the United Kingdom and in 1997, he played for both the Sharks and the Emerging Springboks against the British and Irish Lions during their 1997 tour to South Africa.