Body bags containing the remains of victims, killed in a fire that gutted a slippery factory the day before, are lined up at a makeshift morgue set up at a village hall in suburban Manila on May 14, 2015. [Photo: CFP]

Philippine authorities say they need to run DNA tests to properly identify those killed in a slipper factory fire in Manila this week.

The massive blaze has left 72 people dead.

Philippine interior secretary Mar Roxas has met with the families of the victims.

"The problem is that we cannot identify each of the victims, the name or who the body belongs to, so even though the families would want to bury them in their provinces, we do not know what remains we can give them, that's why we need to finish the DNA testing."

Officials say the fire was caused by sparks from a welding torch which triggered an explosion involving the chemicals used to make the slippers.