And the 26-year-old has revealed he has suffered similar abuse to the threats Harry Redknapp received upon leaving Portsmouth and joining rivals Southampton.
"I have absolutely no idea how they got hold of my number but some of the calls have made me sick to my stomach," he told the Mirror
"I have reported it to officials at the club, but cannot accept that it is coming from people with a balanced state of mind.
"It has infuriated and upset my family and left me wondering what on earth possesses people to do things like that."
Defoe insisted that the main stimulus for his departure from Portsmouth is his desire to return to Redknapp's management; and added that the club's publicly aired financial problems has prompted other players to consider their futures.
"A year ago players were falling over themselves to join Portsmouth," he said. "I know because enough of them were calling me.
"I accept the financial situation isn't good for a lot of clubs but when you start to see players like Sulley Muntari and Lassana Diarra leaving, you start to worry about the effect it is going to have on the team and who is going to be next out the door."
Though Portsmouth have not denied that Defoe looks likely to leave the club, chairman Peter Storrie has rubbished speculation that a £30 million triple bid for Defoe, Peter Crouch and Glen Johnson is going ahead.
"We don't speak about transfers as a rule," he said. "It looks like Jermain wants to go, but this talk about there being a bid from Spurs for Glen and Peter is complete and utter rubbish.
"We do not have to sell anyone, but if anyone wants to go that is a different matter."