The 27-year-old Columbian has been linked with a switch to the Reds, who are thought to want to replace the unsettled Iago Aspas, in the past and there was talk of a move last summer but nothing came of it.
Reds boss Brendan Rodgers is not alone in looking at the striker as Chelsea's former Porto managers Jose Mourinho and Andre Villas-Boas, are also said to be keen to land the forward.
Martinez made it clear that he is keen to test himself at a higher level before he gets too old.
"The years are passing and one day I hope to make a good transfer," Martinez said.
"It clearly depends on Porto, a club that sells its players so well. Leaving or staying depends on Porto but I will only go if there is something concrete."