Rockers and activists Bono and Bob Geldof say the world's biggest industrial countries are failing to keep up with their financial pledges to Africa.

Bono says the G8 countries are "sleepwalking into a crisis of credibility" by not honouring their promises.

The two spoke at a news conference to release a progress report from Bono's Africa advocacy group, DATA (Debt AIDS Trade Africa).

The report says that from 2004 to 2006, the G8 countries contributed less then half of what they promised in order to double Africa aid to $50bn by 2010.

"It's a trend at this point but we have made such a fuss about it and now they know that the world is interested in the minutia of how these promises are being kept," Bono said in an interview with Reuters.

"I think they will pull the nose of the airplane up," he added.

The U2 front man says he hopes the report will be a "cold shower" for the Group of Eight.

Irish singer Geldof said the countries need only make good on the minimum of what they pledged.