The head of the World Trade Organisation has said he will step down on 31st August, a year before his term ends, insisting an early change of leadership would help the body face "new post-COVID realities".

"This is a decision that I do not take lightly," Roberto Azevêdo told member state representatives, according to a written version of his speech.

"It is a personal decision, a family decision," he stressed, adding: "It is not health-related... nor am I pursuing any political opportunities."

The 62-year-old Brazilian career diplomat first took the reins of the global trade body in 2013 and his second term had been due to end in September 2021.

Mr Azevêdo's early departure comes at a time when the Covid-19 pandemic has pushed the global economy and international trade into turmoil, suffering downturns not seen since the Great Depression of the 1930s. 

Global trade, already hit by trade tensions and uncertainties around Brexit, is expected to register "double-digit declines in trade volumes" in nearly all regions this year, the WTO said last month.

The 164-member organisation was meanwhile already in crisis before the pandemic hit, amid raging trade wars and as the United States under President Donald Trump has pushed for dramatic reforms of the Geneva-based body.

The WTO was, for instance, forced to put its dispute settlement appeal system on ice last December after Washington blocked the appointment of new judges, preventing it from reaching a three-judge quorum.

Mr Azevêdo's expected departure "comes at a very bad moment for the institution, as the trade system has become deeply destabilised," Sebastien Jean, head of CEPII think tank, told AFP.

He pointed to "existing tensions, in particular the scathing criticism from the US president, violations of many agreements, the US-China trade war and the paralysis of the appeals body."

He also lamented the many trade measures taken in reaction to the Covid-19 crisis, including a wide range of export restrictions.

Mr Azevêdo, who before his appointment as WTO chief spent five years as his country's ambassador to the organisation, has enjoyed a reputation as a consensus-builder.

During his first term he dedicated much energy to trying to unblock long-deadlocked trade agreements.

The WTO has for nearly two decades failed to conclude the Doha Round of trade liberalisation talks.

However, on Mr Azevêdo's watch, WTO members did finally conclude their first ever multilateral agreement when they reached a deal in Bali in late 2013 on overhauling global customs procedures.

But countries have since then failed to reach any further multilateral agreements, including on fisheries subsidies, and since 2017 the WTO has struggled to deal with a US administration openly hostile to its multilateral approach.

It remains to be seen who will take his place, but many observers are already betting on a candidate from Africa - and against a WTO insider.

Mr Azevêdo's "insider" status "was not necessarily conducive to giving him true influence over the unfolding events," Mr Jean said.

"Azevêdo's mandate has rather been characterised by impotence to stop the destabilising tendencies" facing the global trading system, he said.

One diplomatic source meanwhile told AFP that there appeared to be a clear "consensus" that the successful candidate to take the reins at the WTO should not come from "a big economic power", and certainly not from China or the United States, in light of their trade war.