However, some reports suggest that dozens of detainees could have died from smoke inhalation.
The blaze reportedly started after prisoners set fire to mattresses in an attempt to break out.
Police used tear gas to disperse relatives who had surrounded the station and were trying to break in.
State Official Jesus Santander confirmed a police officer had been shot, and said fire fighters had got the blaze under control.
He said forensic doctors were working to determine how many people had died.
Unofficial death estimates in the media range from 60 to 78.
Venezuela’s prisons are notoriously overcrowded and are known to be filled with weapons, drugs and gangs.
The country has struggled to accommodate its prisoners amidst an ongoing economic crisis, leading to convicts being held at temporary facilities such as the one in Valencia.
Carlos Nieto, head of the association Una Ventana a la Libertad (A Window on Freedom), says some police facilities are overfilled at five times their capacity. (Courtesy BBC)