The CAC (Commonwealth Aircraft Corporation) designed a similar plane to the North American NA-16-2K and called it the Wirraway, which is Aboriginal for challenge. The Wirraway added additional armament, strengthened structure for dive bombing, and under wing bomb racks.
The Royal Australian Air Force (RAAF) knew that they couldn't completely rely on Great Britain to keep them supplied with aircraft so it was decided to start manufacturing their own models. In 1936 a commission went to the United States where they met with North American Aviation, Inc. and selected the NA-33. Two of these were shipped to Australia for testing and an order was placed for 40. These became the CA-1 Wirraway.
The CAC license built the Pratt & Whitney engines for the Wirraway.