Security has been beefed up as the Blue Economy Conference began at the KICC, Nairobi, on Monday.
Inspector General of Police Joseph Boinnet said adequate personnel have been assigned to ensure the security of at least 12,000 delegates.
Police have warned of possible traffic disruptions in the city in the next three days.
A special team of police has been assigned to provide security.
City Hall Way has also been closed till Wednesday.
Eleven heads of state are among the people expected to attend the country’s inaugural ocean economy summit.
Seychelles' President Danny Faure, who was last week named the African Union champion for Blue Economy, and Namibia’s Hage Geingob are among them.
Others are Uganda’s Yoweri Museveni, Congo’s Sassou Nguesso, Somali’s Mohamed Abdullahi Mohamed, and Fiji’s Prime Minister Frank Bainimarama.
Foreign Affairs CS Monica Juma said more than 11,000 delegates had already confirmed participation, exceeding an earlier target of 6,000 delegates.
Canada and Japan will be co-hosting the event with Kenya having each contributed Sh300 million.
Over 50 ministers have confirmed attendance for the three-day event.