Officials had originally put the death toll at 73 following the massive blast on Thursday in Tete province in the country's remote western region near Malawi.
By today, officials had counted 60 bodies in mortuaries as recovery efforts continued.
"In the accident, 108 people were injured, 96 of whom are still being kept in for treatment at Tete Provincial Hospital," government spokesman Mouzinho Saide said at a press conference in Maputo.
"The cabinet has created a commission of inquiry to investigate the circumstances, causes and responsibilities for this accident."
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The driver took a detour and stopped close to the Malawi border in the village of Caphiridzange to sell petrol to local people, a common practice in Mozambique.
"The truck drivers were transferring petrol into a smaller truck and they fled when they noticed there was an (electrical) short circuit," Emilia Moiane, an information ministry director, told AFP.
"Seeing the truck had been abandoned, locals came to syphon petrol off, not knowing that the truck was already burning inside."
One of the truck drivers was from Mozambique and the other from Malawi, officials said.
"What is important now is to take action and help the affected," he said.
Photographs and video footage from the hospital in Tete showed badly burned children arriving for emergency care and adults lying on hospital beds.
"We still have a lot of cases in a critical condition, including children and two pregnant women, out of 38 cases in total," Tete hospital director Veronica de Deus said.
"The vast majority of patients have severe burns. Some have 80 to 90 per cent of their bodies burnt," she said on public broadcaster TVM.