A major crackdown on Australia’s immigration system has been delayed at the last minute, but one migration expert says the national debate is missing the real issue. But Australian National University Migration Hub director Professor Alan Gamlen told Sunrise the focus on net migration risks overlooking the biggest challenge facing Australia’s immigration system. He explained there are two big components to the migration system. He said issues including migrant exploitation, pressure on housing and infrastructure, and concerns about social cohesion are largely tied to the temporary migration system. “That gives some lack of control to government over the temporary visa system,” he said.