David Cameron will step up his bid to win wider approval for the coalition's commitment to aid spending later.
The prime minister will use a speech in Nigeria to insist that "the aid sceptics are wrong" - even as foreign affairs thinktank Chatham House releases a survey revealing how unconvinced voters are about the value of aid spending.
Fifty-seven per cent of voters thought Britain was sending too much aid to developing countries. Just seven per cent thought the UK is spending too little.
"There are some people back at home who don't like Britain's aid commitment," Mr Cameron is expected to say.
"They see us make painful cuts to budgets at home and wonder why we are increasing our spending abroad.
"And they look at where some of our aid money has gone in recent years – on the wrong priorities and into the wrong hands – and think: this is all being wasted.
"They have a point. Some of our money has been wasted. But that's not an argument to stop aid. It's an argument to change the way aid is delivered and that's what we're doing."
His comments come as up to ten million people find their lives at risk in the Horn of Africa crisis.
The Chatham House survey found that most people think the most important focus of British foreign policy should be protecting its borders, however.
It contains a broader criticism of the coalition's approach. Just six per cent think the government's record over the last year has enhanced the UK's reputation, compared to 40% believing it has been damaged.
A key factor in this appears to have been the decision to participate in the western-led military intervention against Muammar Gaddafi in Libya. Sixty-four per cent think Britain should not get involved in pro-democracy uprisings at all.
Former Foreign Office minister Mark Malloch-Brown, who contributed to the analysis, said: "The real challenge of British foreign policy is the need to do more with less.
"In the survey, many still hanker for a role Britain is no longer equipped to play.
"The consequences of cuts have been on embarrassing display as the generals have struggled to mount an adequate British contribution to the Nato Libyan operation."