Yang said China believes North Koreans who cross the border are economic immigrants, not political refugees. He also said his government does not agree with "the politicization and internationalization of the issue."
South Korean President Lee Myung-bak also pressed Yang on the refugee issue at a meeting later in the day, a spokesman said.
While China returns refugees to North Korea, some other countries in the region, such as Mongolia, deport them to South Korea. South Korea gives them refugee status and a government grant to help them get started in a new life.