The parks authority has not confirmed the incident, but on Saturday it imposed an indefinite ban on big game hunting outside the national park from which Cecil, a rare black-maned lion, was lured before being killed on July 1.
"Hunting of lions, leopards and elephant in areas outside of Hwange National Park has been suspended with immediate effect," Edison Chidziya, head of the parks authority, said in a statement.
He added that a man from a private game park had been arrested on suspicion of breaching hunting rules.
The statement did not mention the death of a second lion, but the parks agency source, who is not authorised to speak to the media, said the lion had been illegally killed by a foreign hunter at a game park near Hwange on July 3.