The catalytic cracking unit at Venezuela's 310,000-barrel-per-day (bpd) Cardon refinery is working normally after reduced functioning at the weekend,
state oil company PDVSA said on Wednesday.
A union leader and refinery worker earlier said the unit was shut at the weekend because PDVSA had not paid for deliveries of imported crude it was processing.
But PDVSA said in a statement that "under no circumstances was the Cardon cracker stopped," even though it was operating at a low level.
Cardon and the neighboring Amuay refinery form the 955,000-bpd Paraguana Refining Center.
"We urge national and international public opinion to ignore information and false rumors whose only objective is to try and damage the image and reputation of the
Venezuelan people's main industry," the PDVSA statement added.
(Reporting by Diego Ore, editing by G Crosse)