The 25-year-old, who has scored 17 goals in 31 league appearances this season for Mexican side Jaguares, was reportedly the subject of a bid from the Reds in January.
Martinez had described a move to Anfield as a "fairly good option" and he has now revealed that Porto are also admirers of him.
He told Colombian newspaper Nuevo Estadio: "I am not in any advanced negotiations with Liverpool or Porto but I know they are personally interested.
"I have not spoken to anyone and that goes for my club and my agent.
"In the next few months things should be finalised."
Martinez is said to be available for £4m.