Charles Omondi was detained at the Harare International Airport by immigration on Thursday on allegations that he did not have adequate accreditation papers as required by Zimbabwe Electoral Laws.
The Zimbabwe Electoral Commission is responsible for the accreditation of all journalists intending to cover the polls next Wednesday.
Human rights lawyers said on Thursday they were battling to secure Omondi's release who works for the Nairobi-based the Nation newspaper.
"We sent a lawyer, Wellington Pasipanodya from our media lawyers' network but he was denied to see him," said Jacqueline Chikakano, a legal officer with the Media Institute of Southern Africa Zimbabwe Chapter.
"He was told that he is not on Zimbabwe soil since he is yet to be legally allowed into the country. I called an immigration official they said there is nothing that can be done as he will be deported," she said.
There was no immediate comment from Immigration but sources said Omondi was likely to be deported later Friday.