"So far 94 have died, 178 have been injured," Interior Minister George Saitoti told reporters as he inspected the scene of the deadly blaze near the Rift Valley town of Molo, 150 kilometres (95 miles) northwest of Nairobi.
Bodies burnt beyond recognition were still strewn across the road as emergency services struggled to cope with the number of casualties.
The injured were dispatched to several hospitals in the region, while some were to be airlifted on military planes to Nairobi and extra body bags also had to be sent from the capital, rescuers said.
"Among those killed are four police officers who had gone to the scene to control the crowd scooping fuel," Saitoti said.
According to witnesses and rescue services, a truck carrying petroleum products overturned on the roadside after being involved in an accident late Saturday.
The crashed tanker was soon swarmed by dozens of locals who rushed with jerricans and other makeshift containers to siphon a few litres of free fuel from the spilling truck and a nearby ditch.
Some witness accounts said the spill may have been set ablaze when one member of the crowd lit a cigarette.
Kenya police spokesman Eric Kiraithe said from the scene that the exact circumstances of the accident were still being investigated.
Kenya Red Cross Public Relations officer Titus Mung'ou said: "There were many people at the scene who had gone to scoop fuel, that is when the tanker exploded. The fire seems to have been ignited by something like a matchbox."
"I saw a crowd at the scene of the accident, then I rushed there when I heard there was fuel. I had taken the first jerrican back to my home and when I came back for the second, I heard an explosion and it was like we all caught fire. I don't even know how I got here," 25-year-old Michael Kerich told AFP, lying on a blanket on the floor of Rift Valley provincial hospital in Nakuru.
Such accidents are relatively frequent in Nigeria but the carnage near Molo was the worst such disaster to hit the East African country, which was recently hit by frequent fuel shortages.
"This is a national disaster, it is so unfortunate that we have lost many people in two tragedies in less than a week," Saitoti said.
On Wednesday, a central Nairobi supermarket was completely destroyed by flames, killing at least 25 people.
Four days later, rescuers were still sifting through the rubble to look for the bodies of missing people believed to have been trapped in the inferno.