SYDNEY (Reuters) - Australian Defense Minister David Johnston was thrown out of Prime Minister Tony Abbott's cabinet on Sunday, a month after he embarrassed the government with comments critical of government-owned ship builder ASC.

Abbott also promoted Immigration Minister Scott Morrison to the post of social securities minister in a reshuffle.

"This is a ministry for jobs and families and it is a sign that this government wants the economy to be front and center in the coming year," Abbott said, referring to the social securities portfolio.

(Reporting By Jane Wardell; Editing by Robert Birsel)