Outgoing British Prime Minister Tony Blair on Thursday appealed for concerted efforts by wealth countries, Africa itself and other powers to help the world's poorest continent overcome its plight.

Delivering a key speech focusing on Africa during his visit to South Africa, Blair also expressed concerns over situations in Sudan's Darfur region and in Zimbabwe, urging for actions to improve security and stability in Africa.

The wealthy nations, particularly Group of Eight (G8)industrialized nations, must be "bolder" to deliver their promises on aid and development to bring "real transformational change" in Africa in the years to come, Blair said.

"If we do this, and Africa responds as an equal partner, we will have set a strategic goal that in time we will achieve," he said in the speech delivered at the University of South Africa's Business School in Johannesburg.

"But if we give up, we will lose the chance in this continent --rich as it is -- though its people are poor -- for our values to take root. It would be a calamitous misjudgment," he said.

His call came amid concern that rich nations' ambitious pledges on aid and development, made at the 2005 G8 Summit in Gleneagles, Scotland, chaired by Britain, were falling short.

Blair, who has been widely credited for his leadership on Africa during his 10 years in power, persuaded his fellow G8 leaders in 2005 to pledge for a substantial increase in aid to Africa and debt relief by 2010.

Progress had been made, he said, notably in granting 38 billion U.S. dollars in debt relief to 18 African nations.

But G8 and EU leaders still need to reaffirm their commitment to increase aid in areas like HIV/AIDS treatment programs and universal primary school education.

African governments should also deliver their promises to consolidate democracy, ensure good governance, fight corruption and encourage the private sector to grow, he said.

Blair emphasized the role China can play in Africa.

"In a continent in which the power of China is rising dramatically, we can work with China to serve the development of Africa in a way which benefits us all," he said.

Blair said the African issue of conflict resolution and peace-keeping, particularly in Darfur, Sudan, must be addressed more urgently.

"No conflict demonstrates the need for action more than Darfur," he said, urging the Sudanese government not to "obstruct any effort made to reinforce the AU's ability to improve security and stability (in Darfur)."

He also asked for more international solutions to financial crisis the African Union (AU) peace-keeping operations are facing.

On crisis in Zimbabwe, Blair said he "welcomes the determination of the countries of Southern Africa to tackle Zimbabwe's problem through SADC, and (South African) President Thabo Mbeki's leadership bringing the two parties together."

"We support SADC's efforts to develop a clear plan ... The international community must be prepared to help rebuild the shattered country," he said.