Abdoulaye Bio-Tchane, director of the IMF's Africa department, welcomed the $60-billion pledged last week in Germany by leaders of the Group of Eight (G8) industrialised nations to fight AIDS, malaria and tuberculosis.

In addition to pledges made two years ago at a G8 summit in Gleneagles, Scotland, that should bring total aid to developing countries disbursed by 2010 to $50-billion per year, he said.

"There was an additional commitment and I think we should recognise that ... We at the Fund are urging donors to stand by their commitment," Bio-Tchane said, citing research showing that aid to Africa had remained flat. "We are not yet in the scale-up mode that was described at the summit of Gleneagles."

Major donors vowed at a meeting in France two years ago to make aid payments more predictable and to harmonise their conditions for disbursing aid. The IMF was still lobbying for donors to stick to the so-called Paris Declaration.

"We need to see progress with the commitments in the declaration," Bio-Tchane told Reuters. "African countries can't plan if they don't have predictable resources, whether they are domestic or international. They can't plan if there will be a shortfall of aid because the conditions are not harmonised."

With no timeline set for the G8 aid, some development campaigners such as Oxfam criticised it as a hollow pledge aimed more at grabbing headlines than helping the world's poorest.

In its annual report, the IMF predicted that sub-Saharan Africa's economy would grow by 6,7 percent this year, the fastest rate in a decade, thanks not only to high commodities prices but also to prudent policies.

That still remains below the threshold of seven percent economic growth needed for Africa to attain the UN Millenium Goal of halving extreme poverty by 2015, the Fund estimates.

The return to growth of major African states recovering from armed conflict, such as Ivory Coast and Democratic Republic of Congo (DRC), should foster activity in neighbouring countries.

"Having the DRC and Ivory Coast as effective players should make a big difference to Africa as a whole," said Bio-Tchane, singling out mineral-rich Congo, which borders nine nations at the heart of Africa, as key to the continent's future.

But tariff barriers continued to severely limit trade within the continent and hamper growth, despite repeated appeals from the Fund to remove obstacles to trade, including lack of infrastructure and widespread corruption.

"There hasn't been any significant move on that front," Bio-Tchane said. "It is really sad to see that Africans can't trade more among themselves. It is really the first stage of growth if trade can be encouraged by lifting these administrative and sometimes physical hurdles."

Total foreign direct investment to the continent surged 78 percent to $31 billion in 2005, according to UN figures, but perceptions of corruption deter investors. In 2006, half of the world's top 20 most-corrupt countries were in Africa, according to Berlin-based Transparency International.