Tim Ticar, a local tourism officer, said 6,000 foreign and local tourists were stranded on the popular resort island of Boracay, one of the tourist spots in the typhoon's path.
The storm's sustained winds weakened Saturday to 163 kph (101 mph) with stronger gusts as it blew farther away from the Philippines toward Vietnam.
Haiyan was forecast to hit central Vietnam's coast on Sunday afternoon, making its way to the northern part of the country before likely weakening to a tropical storm.
Vietnamese authorities in four central provinces were evacuating more than 500,000 people from high-risk areas to government buildings, schools and other concrete homes able to withstand strong winds.
"The evacuation is being conducted with urgency," disaster official Nguyen Thi Yen Linh said from central Danang City, where some 76,000 were being moved to safety.
Hundreds of thousands of others were being taken to shelters in the provinces of Quang Ngai, Quang Nam and Thua Thien Hue. Schools were closed and two deputy prime ministers were sent to the region to direct the preparations.