The tanker overturned along a road in Totota town, about 130km (80 miles) from the capital, Monrovia.
It burst into flames soon after people rushed to the site to scoop fuel from the tanker, eyewitnesses said.
A pregnant woman was among the dead, and some of the bodies were burnt to ashes, Dr Kateh said.
He told local broadcaster Super Bongese TV that more than 83 people had been admitted to hospital for their injuries following Tuesday’s disaster.
Patients with more serious injuries had been transferred to hospitals in Monrovia for treatment, Dr Kateh added.
The cause of the crash is unclear.
Video footage shows that a large number of people, including children, had gathered around the tanker after it overturned.
Some had buckets and jerrycans and others were on top of the tanker when it burst into flames.
Liberia’s President George Weah has expressed his condolences to the families of the dead, saying he found images of the tragedy “deeply disturbing”, his office says.
Mr Weah has given the health authorities his “full backing to beef up manpower and equipment where necessary in their frantic effort to save lives”, the statement adds.
