The man who has been heading up the Government's border protection taskforce, General Angus Campbell, has been promoted to Chief of the Army.

Prime Minister Tony Abbott said a new chief of Operation Sovereign Borders would be announced next week, when the Government would also likely clarify whether a new security department would be established.

Lieutenant General Campbell will take up the new post in May, replacing David Morrison, who has been in the position for nearly four years.

The Government also announced Air Vice-Marshal Gavin Davies would take over as the new chief of the Royal Australian Air Force in July, from Air Marshal Geoff Brown.

Chief of the Defence Force Air Chief Marshal Mark Binskin paid tribute to those leaving the positions, saying they had been "very strong supporters of reform", and welcomed their replacements.

"It finalises the command team in the Defence Force," he said.

"It is a command team I have every confidence in and I know will be positioned to confront the challenges we have over the next couple of years, predominantly in the reform space but also the operation space."

Mr Abbott said the new chiefs were "outstanding officers", praising General Campbell for his role at the helm of Operation Sovereign Borders.

"He has done exceptional work in this very difficult job," he said.

Mr Abbott said Air Vice-Marshal Gavin Davies had been a "pilot of distinction".

"He has had, more recently, a series of senior commands including senior roles in our air operations in the Middle East," he said.

Prime Minister praises retiring Morrison

Mr Abbott also recognised the contribution of David Morrison, who will leave the Defence Force after a 36-year career.

Loading...

"He is a soldier's soldier," Mr Abbott said.

"But he's also been a modern soldier's soldier who has very much wanted the Army to move into the modern world.

"No-one who saw his famous talk to the Defence Forces, 'the standard you walk past is the standard you accept' will ever doubt his commitment to making our Army a modern as well as effective fighting force."

The Prime Minister said the departing Air Force Chief, Geoff Brown, was leaving at a time when the Air Force had "never been more capable".

"These two distinguished officers can feel very, very proud of their contribution to our armed forces and I salute them as they conclude their long and distinguished military careers," Mr Abbott said.