The fiery crash occurred about 1 p.m. local time on the Benin-Sagamu-Lagos expressway, The Guardian newspaper in Lagos reported. The tanker and bus were stationary when the trailer slammed into them.
Several other vehicles were also gutted by the subsequent fire, the newspaper said.
"Three were rescued, and we estimate that over 60 persons died," said an official of the Federal Road Safety Commission, who spoke on condition of anonymity because he was not authorized to speak officially. "Three others in the trailer died. As I speak, the whole place is blocked; fire fighters cannot even access the area.
"The whole place is still burning."
He said the trailer truck blew a tire before it crashed.
Meanwhile, the Daily Trust reported 18 passengers were killed Wednesday when two buses collided a head-on at Sheda village, along Abuja-Lokoja road.
Nine other passengers were hospitalized with injuries.