The Nobel laureate, writing in Britain's Observer, 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".
Archbishop Emeritus 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.
"The cost of the decision to rid Iraq of its by-all-accounts despotic and murderous leader has been staggering … More than 110–000 Iraqis have died in the conflict since 2003 and millions have been displaced. By the end of last year, nearly 4–500 American soldiers had been killed and more than 32–000 wounded," Tutu wrote in the Sunday weekly.
"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."
"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."
Tutu, a long-standing vocal critic of the Iraq war, also defended his decision to not attend a South African conference on leadership last week because Blair was attending.
"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," he added.
The Nobel Peace Prize winner also argued that the US-led 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."
Meanwhile, Blair said on Sunday Tutu's comments were completely wrong.
In a statement, Blair said: "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 added: "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."
Tutu questioned in his article the different standards for bringing African and Asian leaders to justice, and for Western leaders. – Sapa-dpa, AFP