China on Thursday welcomed the appointment of Brazilian diplomat Roberto Azevedo to head the World Trade Organization, with state media saying it showed the growing clout of emerging economies.

Foreign ministry spokeswoman Hua Chunying said China "welcomes" the choice while the Xinhua news agency called his selection "something worth celebrating" as the first time a candidate from a BRICS nation would hold the post.

The BRICS grouping is made up of Brazil, Russia, India, China and South Africa.

Azevedo's appointment "further testifies to the widely recognised fact that emerging economies are playing an increasingly important role in global economic activities", Xinhua said.

Azevedo, 55, will take the helm of a 159-member grouping still trying to find its way after the collapse of the Doha round of global trade talks in 2008. The current rules underpinning global trade date from 1994.

But Xinhua cautioned that in the face of protectionism, the Brazilian faced a daunting task to achieve consensus.

"No one should be ignorant about the fact that Azevedo's efforts to revive stalled trade talks and fight disruptive protectionist measures can succeed only if major global trade powers rally behind him and iron out their differences for the global development," it said.

Hua told reporters that China would "support the work of the director-general and play a constructive role in multilateral trade affairs".

The commerce ministry said in a statement it hoped Azevedo would "prioritise the patching up of differences between developed and developing members and... the finalising of the Doha round of talks in a comprehensive manner".

It also called on the incoming WTO leader to resist trade protectionism to help drive global recovery.

Azevedo emerged victorious on Wednesday as the consensus choice of WTO members and will replace Frenchman Pascal Lamy, a former EU trade commissioner, on September 1 as director-general.