Indonesia's army chief of staff was promoted to head of the military Wednesday, breaking with a tradition that saw the job rotated between branches of the forces and raising concerns about the army's growing influence.

General Gatot Nurmantyo was sworn in as armed forces chief by President Joko Widodo at a ceremony in the capital Jakarta and replaces General Moeldoko, who had also been a senior figure in the army.

The job was expected to go to the air force chief, and the decision to appoint Nurmantyo has sparked fears about the army's increasing influence almost two decades after it was stripped of much of its power following the downfall of dictator Suharto, himself a general.

"I think following the tradition of rotation is better," said Hendardi, chairman of rights group the Setara Institute who goes by one name, adding that the army was getting "privileged" treatment.

He said that Widodo, known universally as Jokowi, was "playing politics" and seeking to shore up his weakened position by getting closer to the army.

The election last year of Widodo, Indonesia's first leader from outside the political and military elites, fuelled hopes of a new era in the graft-ridden country but his administration has beset by crises and criticised for a series of policy flip-flops.

With the end of authoritarian rule in 1998 and the introduction of democracy, serving military members lost the right to take on senior political roles and were limited to defence roles.

Indonesia's new leaders also decided to rotate the job of armed forces chief between the three branches of the military to ensure that none became too powerful, in particular the influential army.

But by installing an army figure as head of the military for a second consecutive time, Widodo has broken with that practice.

Also on Wednesday, Widodo swore in retired army general Sutiyoso as the country's new intelligence chief -- another figure with long-standing links to the army.

The controversy over Nurmantyo followed recent concerns about the rising influence of the Indonesian military in public life more generally, with the armed forces signing agreements with the government to guard key infrastructure and help in the fight against drugs.