London on Tuesday slashed 16 countries including Russia and China from the list of nations it gives financial aid to and said it would no longer fund four "irrelevant" UN aid organisations.
Angola and Vietnam are also among countries that will see their aid budgets phased out between now and 2016.
International Development Secretary Andrew Mitchell said the government was halting contributions to the four United Nations aid organizations because they "performed poorly or failed to demonstrate relevance".
He told parliament it was "no longer acceptable" for Britain to fund the UN Industrial Development Organization, UN-Habitat, the International Labor Organization, and the UN International Strategy for Disaster Reduction.
The cut in funding to the UN bodies is expected to save more than £50 million.
Under the new aid policy, Britain will spend more in war-torn countries like Afghanistan and Somalia to provide greater security for British interests.
"Aid can perform miracles but it must be well spent and properly targeted," Mitchell said.
He was forced to fend off claims from some aid groups that the government was putting Britain's security concerns ahead of aid priorities.
World Development Movement head of policy Julian Oram said: "What we are concerned about is the focus on a smaller number of countries, which actually takes money away from some of the world's poorest countries, like Niger, Angola and Cambodia and channels it into countries where there is deemed to be a higher security risk to the UK.
"The securitization of aid is a real concern under the outcomes of this review."
But Mitchell responded: "In terms of the suggestion that we are securitizing aid, we are dealing with parts of the world where people are doubly cursed -- not only because they live in extreme poverty but also because they live in very conflicted societies."
He added: "This is about value for money. It is about ensuring that, for every pound we take off hard-pressed taxpayers, we really do deliver 100 pence of value.
"We have got to be able to explain and articulate to the people who are paying for this why we are spending the money."