"Seven bodies have been found inside a chemical tank at a factory in Korangi Industrial area," said Deputy Inspector-General Muneer Sheikh.
The men had been identified as the owner of the pickle factory, Mehtab, and six workers, said Senior Superintendent of Police (SSP) Junaid Sheikh.
Rescue workers said they acted upon receiving information about the presence of several bodies inside the factory, the News reported.
It was unclear if the men had fallen inside the tank or had been dumped there.
He said that police was carrying out further investigation to confirm out how the incident took place.
Seemi Jamali, head of emergency at the Jinnah Hospital where the bodies were taken, said it appeared that the men had died from suffocation, but the cause of death could only be confirmed following postmortem.