Late Pope John Paul II gets flowers from his would-be assassin
Mehmet Ali Agca, the Turkish man who attempted to assassinate Pope John Paul II in 1981, holds a copy of the Bible during a press conference in Istanbul on November 27, 2014 (AFP)

Mehmet Ali Agca, the Turkish former extremist who attempted to assassinate Pope John Paul II, on Saturday laid flowers on the late pontiff's tomb.

The latest highly publicised act of contrition by Agca came 31 years to the day after John Paul visited him in prison in Rome to forgive him for the 1981 shooting that nearly killed the leader of the world's Catholics.

Agca, then 23, shot the pope twice from close range in St Peter's Square, one bullet passing through his abdomen and another narrowly missing his heart.

He arrived back in Rome unexpectedly on Saturday and presented himself to police to declare his intention to lay the flowers.

"I felt the need to make this gesture," he told police, according to Italian media who had been tipped off in advance about his visit.

Agca requested a meeting with Pope Francis when the current pontiff visited Turkey last month. That was declined as was a fresh request for an audience this weekend in Rome.

"He has put flowers on the tomb of John Paul II. I think that is enough," Francis's spokesman, Federico Lombardi, told La Repubblica.

The motive for Agca's 1981 attack on the pope remains a mystery. He served nearly three decades in prisons in Italy and Turkey and is widely considered to be mentally disturbed.

He was on the run from the Turkish authorities over a string of crimes and his links to the far-right Grey Wolves movement at the time of his assassination attempt.