"Michael Thawley [an Officer of the Order of Australia] has advised me that he wishes to return to the private sector, and will be leaving the Department of the Prime Minister and Cabinet in late January 2016," Malcolm Turnbull said in a statement.
Peter Varghese will be stepping down as Secretary of the Department of Foreign Affairs and Trade in July 2016, the prime minister added.
According to Turnbull, Drew Clarke, secretary of the communications department, will be appointed his new chief of staff.
Malcolm Turnbull replaced Tony Abbott as prime minister of Australia in September after a vote in the ruling Liberal party.
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