Vice Admiral David Johnston will take over in July from General Angus Campbell, the longest-serving head of the defence force.

The changes at the top come after a royal commission into suicides at defence, during which General Campbell apologised unreservedly for failings in the military.

Vice Admiral Johnston's appointment marks the first time in 22 years the chief of defence force has come from the Navy, which will be at the forefront of the AUKUS alliance that is scheduled to deliver nuclear submarines in a $368 billion program.

"I am very conscious of the responsibility that comes with the role, the strategic environment in which we find ourselves and most particularly the responsibility I have to the extraordinary men and women in the Australian Defence Force and the families who support them," he said.

The vice admiral, who is the defence force deputy chief, said he was committed to culture and wellbeing within the military, along with the environment for personnel.

"We have been participating in the Royal Commission into Defence and Veteran Suicide, presenting evidence as a component of that," he said.

"We recognise the importance of continuing to improve so that people come to work in a respectful environment in a high-performing team where they can do their best."

Prime Minister Anthony Albanese heralded the appointment.

"Vice Admiral Johnson has consistently distinguished himself with his capacity to ensure that different elements of defence work together," Mr Albanese said.

"His understanding of integrated defence will be critical to delivering on the priorities and recommendations of the defence strategic review, ensuring our defence force has the right capabilities and the right leadership to meet the challenges ahead."

Vice Admiral Johnston's elevation has prompted a shake-up of senior roles in the defence force.

Air Marshal Robert Chipman, who previously served as Chief of the Air Force, will become the next Vice Chief of the Australian Defence Force.

Air Vice-Marshal Stephen Chappell will be appointed as the next chief of the Royal Australian Air Force.

Vice Admiral Johnston joined the military in 1978 aged 16 and was named vice-chief of the defence force in 2018, previously serving in Iraq and Afghanistan.

Defence Minister Richard Marles said Vice Admiral Johnston had been pivotal to reform within the military.

"He has been in the engine room of all the work that we have done over the last two years and this is a moment where we need a safe pair of hands and deep experience to take our defence force forward," he said.

"David has been at the very heart of reshaping the Australian Defence Force, both in terms of culture and also, importantly, as the vice chief of the defence force, in terms of the platforms and capabilities that we are seeking to acquire."

Opposition Leader Peter Dutton welcomed Vice Admiral Johnston's appointment.

"As Australia faces increasing challenging strategic circumstances, we need strong leaders who will ensure our ADF is well-equipped with the capabilities and personnel needed to defend our nation," he said.

Mr Albanese paid tribute to General Campbell, who served in the top job since 2018.

"He has earned the respect and deep gratitude of Australia and we wish him all the very best for his future," he said.

RECENT CHIEFS OF DEFENCE

* General Peter Cosgrove (Army) 2002-2005

* Air Chief Marshal Angus Houston (Air Force) 2005-2011

* General David Hurley (Army) 2011-2014

* Air Chief Marshal Mark Binskin (Air Force) 2014-2018

* General Angus Campbell (Army) 2018-2024

* Admiral David Johnston (Navy) 2024-

Australian Associated Press