Archbishop Desmond Tutu called Sunday for former prime minister Tony Blair and former US president George W Bush to face trial in The Hague for their role in the Iraq war.
The South African peace icon, writing in The Observer newspaper, accused the pair of lying about weapons of mass destruction and said the invasion left the world more destabilised and divided "than any other conflict in history".
Tutu argued that different standards appeared to apply for prosecuting African leaders than western counterparts, and added that the death toll during and after the Iraq conflict was sufficient for Blair and Bush to face trial.
"On these grounds alone, in a consistent world, those responsible for this suffering and loss of life should be treading the same path as some of their African and Asian peers who have been made to answer for their actions in The Hague," Tutu wrote in the weekly Sunday newspaper.
"But even greater costs have been exacted beyond the killing fields, in the hardened hearts and minds of members of the human family across the world."
However, Blair responded in a statement saying that "this is the same argument we have had many times with nothing new to say".
Tutu, a long-standing vocal critic of the Iraq war, had snubbed Blair last week, pulling out of a South African conference on leadership last week because the ex-premier was attending.
The peace icon said he had boycotted the event in protest at Blair's "morally indefensible" support of the US-led 2003 Iraq invasion.
The archbishop added on Sunday: "I did not deem it appropriate to have this discussion.
"As the date drew nearer, I felt an increasingly profound sense of discomfort about attending a summit on 'leadership' with Mr Blair."
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He added: "Leadership and morality are indivisible. Good leaders are the custodians of morality.
"The question is not whether Saddam Hussein was good or bad or how many of his people he massacred. The point is that Mr Bush and Mr Blair should not have allowed themselves to stoop to his immoral level.
"If it is acceptable for leaders to take drastic action on the basis of a lie, without an acknowledgement or an apology when they are found out, what should we teach our children?"
The Nobel Peace Prize winner also argued that the 2003 Iraq war to oust Saddam Hussein had created the backdrop for civil war in Syria, and a potential wider Middle East crisis involving Iran.
"The then-leaders of the US and UK fabricated the grounds to behave like playground bullies and drive us further apart," he wrote.
"They have driven us to the edge of a precipice where we now stand -- with the spectre of Syria and Iran before us."
Blair issued a stern defence on Sunday in response to the article.
"To repeat the old canard that we lied about the intelligence is completely wrong as every single independent analysis of the evidence has shown," he said.
"And to say that the fact that Saddam massacred hundreds of thousands of his citizens is irrelevant to the morality of removing him is bizarre.
"We have just had the memorials both of the Halabja massacre where thousands of people were murdered in one day by Saddam's use of chemical weapons; and that of the Iran-Iraq war where casualties numbered up to a million including many killed by chemical weapons.
"In addition his slaughter of his political opponents, the treatment of the Marsh Arabs and the systematic torture of his people make the case for removing him morally strong. But the basis of action was as stated at the time."