China's defence ministry announced Thursday further reshuffling of the top military bosses, reflecting bargaining among the country's top leadership ahead of a power transfer next month.

The heads of four top army departments were changed, with the new appointees certain to gain a position on China's highest military body, the Central Military Commission.

Zhang Youxia, 62, a general thought to have close ties with Xi Jinping, who is set to take over as leader of China's ruling Communist party next month, became head of the Armaments Department, which oversees weapons procurement.

The appointment clears a path for the department's previous head, Chang Wanquan, 63, considered to be a protege of outgoing Communist party leader Hu Jintao, to become a powerful vice-chairman of the Central Military Commission.

The position of vice-chairman traditionally ensures a seat on China's Politburo, a group of 25 people who oversee the ruling Communist party. The Politburo is set for a major reshuffle at the party's congress next month.

Steve Tsang, professor of contemporary Chinese studies at Britain's University of Nottingham, said the appointments reflected a sidelining of more extreme commanders, as well as continued bargaining between Xi and Hu.

For example, Zhang Yang, former head of a military area in southern China, was promoted to head the army's General Political Department ahead of Liu Yuan, a general connected to disgraced politician Bo Xilai.

"These promotions have been agreed to by Hu Jintao and Xi Jinping, and show they are finally agreed on most of the positions in the Central Military Commission," said Tsang.

"What was important about Liu Yuan is that he was quite nationalistic, and in the ballpark where he could be promoted... we are not seeing the promotion of generals known to be outspoken nationalists."

Fang Fenghui, formerly a military commander in Beijing, became the army's chief of general staff, and Zhao Keshi, formerly commander of a military area in eastern China, is now the head of the army's General Logistics Department.

The Defence Ministry's announcement came two days after it named General Ma Xiaotian as the new head of China's airforce and appointed a new military chief in the southwestern Chengdu military zone, which includes most of Tibet.

China has increased investment in its 2.3-million-strong army as part of a modernisation drive, previously saying that military spending would top $100 billion in 2012, up 11.2 percent from last year.