The E-3 classification applies only to nationals of Australia. Like the H-1B category, the employee must be coming to the United States solely to perform services in a specialty occupation which should require the application of knowledge in a professional field and attainment of at least a Bachelor's degree.
The O-1 visa category is available for those foreign nationals who meet the U.S. Citizenship and Immigration Services definition of "extraordinary ability". The individual meeting such definition has a level of expertise indicating that the person is one of the small percentage who has risen to the very top of the field of endeavor. The person qualifying for O-1 status will have sustained national or international recognition of his or her accomplishments in the field, and will be required to prepare and submit substantial documentation of those achievements.
The O-1 classification is suitable for faculty level research scholars who have extraordinary ability in the sciences and who will be working on an 'event' or project that requires someone of that caliber. Clinical faculty with significant research responsibilities, as well as teaching and patient care duties, may also qualify for the O-1 classification.
The North American Free Trade Agreement created the TN-1 visa category for citizens of Mexico and Canada. The TN-1 category allows Canadian and Mexican nationals in a prescribed set of occupations to come to the United States temporarily. Some of the eligible occupations include nurses, physical therapists, medical technologists, professors and physicians conducting research, among others.