Van Aswegen made his debut for the Springboks during the 1981 tour of New Zealand in the first test on 15 August 1981 at Lancaster Park in Christchurch. He played his second and last test match for the Springboks against the South American Jaguars on 3 April 1982 at the Free State Stadium in Bloemfontein when he replaced his provincial team mate, Hempies du Toit after 27 minutes in the second half. Van Aswegen also played in eight tour matches for the Springboks.