Poor versions of the songs entitled 'Watch Yo Mouth' and 'NY '87' have been previously leaked, but this is the first time that the lyrics attacking other rappers can be clearly heard, according to Uncover.
In 'Watch Yo Mouth', the late Shakur takes aim at rivals Dr Dre, Nas, De La Soul and Biggie Smalls.
A man called Dexter Isaac confessed earlier this month to shooting and robbing Shakur on behalf of gangster James 'Jimmy Henchman' Rosemond. He issued a statement to the star's family, saying he wanted to "apologise... for the mistake" in order to give their "mothers some closure".
Rosemond's lawyer later denied all the claims, saying they were a "flat-out lie". He added: "Dexter Isaac is not claiming this 17 years later to clear his conscience. He's doing it because he's told anybody who will listen he doesn't want to die in prison. He has kids and wants to work off his sentence. He can't be trusted."
Shakur was reported to have been seen alive and well in New Zealand earlier this month. The news story eventually turned out to be fake.
Listen to 'Watch Yo Mouth' by Tupac Shakur below (contains strong language):
Listen to 'NY '87'by Tupac Shakur below (contains strong language):