Brendan Sargeant, Defence stratgegist, dies while swimming on NSW coast

The Canberra Times understands he died on the NSW coast after becoming caught in a rip.

Tributes flowed from the ANU where Professor Sargeant was head the Strategic and Defence Studies Centre following a career in Defence as deputy secretary and associated secretary.

Much of Australia's contemporary Defence strategy, including the 2013 White Paper and the Force Structure Review were principally authored or overseen by Mr Sergeant before he exited the department in 2017.

Chief of Defence General Angus Campbell and Defence department secretary Greg Moriarty said Mr Sergeant's legacy to Defence was substantial.

"Defence will always remember Brendan Sargeant as a man of integrity, with a purposeful and searching mind and great insight into the strategic challenges facing Australia," they said in a joint statement.

His White Paper shed new light on changing circumstances in the region, they said, including emerging cyber threats and implications of the global financial crisis, and he helped lead a major organisational reform agenda in the department which has helped to modernise and position Defence to better contend with today's security threats.

They noted his contributions did not end after leaving Defence for academia, and was a mentor to many in the National Security community.

ANU vice-chancellor Prof Brian Schmidt said the university community had lost "a giant of the university, of Canberra and of the nation".

"Brendan was well-loved and well-regarded by many here at ANU, as well as in defence circles," Dr Schmidt said.

"Brendan was not only a leader in his field - he was a true leader on our campus and a great friend to his colleagues, peers, our university and to me, personally.

"We are deeply saddened by this unexpected loss and send our heartfelt well wishes to Brendan's family, friends and loved ones."

Tributes also came from College of Asia and the Pacific dean Professor Helen Sullivan and Coral Bell School director Professor Toni Erskine, who described him as a wealth of experience and knowledge with the generosity to share both.

Memorial service details were not yet finalised on Monday.

Our journalists work hard to provide local, up-to-date news to the community. This is how you can continue to access our trusted content: