In a statement, Samaras targets Tsipras, saying he is responsible for setting up the “miserable conspiracy”.
The case of the Novartis pharmaceuticals giant and allegations that former top government officials — including Samaras — were receiving bribes has shaken Greece’s political world.
A preliminary parliamentary committee to investigate the Novartis case will be set up next week.
The case is built around the testimonies of three former Novartis employees who testified to the Supreme Court Prosecution and are in a witness protection scheme.
The allegations contained in the testimonies have been angrily denied by all those implicated.
Samaras warned that the use of testimonies to destroy political opponents will undermine democracy in Greece.
Any government will be able to use false witnesses to exterminate its political opponents, he added.
“That would be the end of democracy in our country. Mr. Tsipras must not be allowed to impose a Maduro-like regime in Greece. I will not play the game of those who hurl mud at opponents,” Samaras said.