(Reuters) -The head of the World Trade Organization (WTO) on Tuesday called for reforms of the 30-year-old institution, highlighting its consensus rule that requires unanimous agreement among members to secure global trade deals.

"We need to reform the system, we cannot be complacent," WTO Director-General Ngozi Okonjo-Iweala told the Future Investment Initiative conference in Riyadh. 

"We need to reform some of the ways we do business like our consensus decision-making system which is practised as unanimity - everyone has to agree - so it really slows down decision making," she said.

She also urged the WTO's 166 members to engage with the United States on its criticisms of the watchdog, many of which she acknowledged as valid.

Okonjo-Iweala repeated that the global trading system was undergoing the biggest disruption in eight decades, describing it as "battered but not broken".

She hailed the fact that more of its members had not resorted to retaliatory measures in the face of U.S. President Donald Trump's tariffs on trading partners. 

"The fact that almost three-quarters of world goods trade is still going on on WTO terms is amazing," she said.