There is a 40¿ rotation of regional maximum horizontal stress (&sgr;hmax) orientation between the western end of the Australian North West Continental Shelf (Carnarvon Basin) and its eastern end (Bonaparte Basin). A total of 625 borehole breakouts covering a cumulative length of 7.7 km in 42 wells in the Carnarvon Basin indicates a &sgr;hmax orientation of 090¿--100 ¿N. A total of 616 borehole breakouts over 6.8 km in 46 wells in the Bonaparte Basin indicates a &sgr;hmax orientation of 055 ¿N--060 ¿N. Together with extant data from the World Stress Map, these results indicate that regional &sgr;hmax orientation is 050¿--060 ¿N from New Guinea westward through the Bonaparte Basin to the Canning Basin (central North West Shelf). Between the Canning Basin and the Carnarvon Basin, &sgr;hmax rotates to 090¿--100 ¿N. The parallelism of &sgr;hmax orientation in the Bonaparte Basin to the Australia/Banda Arc collisional zone indicates that this collision is not generating significant net push. Rather, the 050¿--060 ¿N &sgr;hmax orientation of much of the northern Australian margin is probably controlled by the more mature New Guinea orogen to which it is approximately orthogonal. The observed rotation of &sgr;hmax can be explained solely by the focusing of the forces balancing ridge push along collisional segments of the northeastern boundary of the Indo-Australian Plate (such as the New Guinea orogen). Although not required to account for the observed stress rotation, a slab pull force from oceanic Indo-Australian Plate being subducted beneath the Sunda Arc cannot be dismissed.¿ 1997 American Geophysical Union