Baccouche told private radio station Jawhara FM he had "irrefutable proof" that Sofiene Chourabi and Nadhir Ktari - who have been missing in eastern Libya since last September - "are alive."
"We are trying to bring them back to Tunisia," he added, declining to give further details.
In January, the Libyan branch of IS claimed to have executed the pair. The announcement triggered shock and disbelief in Tunisia where rallies were held as people demanded proof of their deaths.
|In January, IS claimed to have executed two Tunisian journalists missing in Libya|
In April, Libya's internationally recognised government said five detainees had admitted to killing five local television reporters as well as the two Tunisians.
Chourabi, an investigative journalist and blogger who was active during Tunisia's 2011 revolution, and photographer Ktari went missing in the Ajdabiya district of eastern Libya on September 8, 2014.
Days earlier, they had been seized by an armed group near the northeastern town of Brega, but were released before disappearing again.