Singapore is the best place in the world to carry out business but significant barriers remain in the rest of the Asean region, a study released in Vietnam on Thursday said.
The World Economic Forum index ranked 125 countries based on their performance in four main areas: market access, border administration, transport and communications infrastructure and general business environment.
Singapore kept the top rank it held in last year's study, but five other members of the Association of Southeast Asian Nations (Asean) fell.
Vietnam improved from 89th to 71st largely because of its accession to the World Trade Organization three years ago, Thierry Geiger, a co-author of the study, told a news conference.
But he said barriers to trade in Asean "remain many and significant", primarily in border administration and transport infrastructure.