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."

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."