Rexlon Gatchalian, mayor of Valenzuela city in Manila, said he was hoping some of the missing workers, most of whom were trapped by flames and thick black smoke, had managed to escape Wednesday's fire.
"We're still hoping that the number of missing, 26, will still go down," Gatchalian said. The death toll had stood at 31 late on Wednesday.
The two-storey factory is owned by Kentex Manufacturing Inc, which makes flip-flops and slippers.