MPs have warned the UK cannot continue to contribute a disproportionate amount of humanitarian aid to Syria without other poor countries losing out on assistance.
The International Development Committee said countries such as France, Spain and Italy had "manifestly failed to pull their weight" in contributing to alleviating the crisis brought on by the civil war in Syria.
"The UK should do everything in its power to encourage other countries to increase their contributions," the committee's latest report said.
The UK has already contributed £600m to the relief effort - the second highest total after the United States.
The United Nations estimates almost 11 million people are in need of help as a result of the crisis, with 2.5 million Syrians now living as refugees in neighbouring countries.
The South African government have accused their British counterparts of failing to go through the proper channels before announcing an end to the country's annual £19 million payment in Official Development Aid.
The Department of International Relations and Co-operation said it had noted the UK announcement "with regret", adding that the "major decision" had "far reaching implications on the projects that are current running" in South Africa.
A statement from the department added:
The department said there was "no doubt" that the UK's announcement "will affect how our bilateral relations going forward will be conducted".
But it said it would use the forthcoming forum to "clear up this matter among others".
Britain has become embroiled in a diplomatic row with South Africa after announcing it will scrap £19 million in annual overseas aid to the country from 2015.
International Development Secretary Justine Greening sparked an angry reaction from Pretoria after declaring the country was now "in a position to fund its own development".
South Africa's Department of International Relations and Co-operation said Britain's decision to pull the plug on aid was "tantamount to redefining our relationship".
Foreign Secretary William Hague has this morning played down the spat, blaming it on "bureaucratic confusion".
The UK's direct aid to South Africa will end in 2015, International Development Secretary Justine Greening will announce.
The Government's aid programme to South Africa is currently worth £19 million a year, down from its peak of more than £40 million in 2003, and has focused on reducing the mortality rate among women giving birth, as well as supporting businesses.
Mr Greening will tell a conference of African ministers and business leaders in London tomorrow that the relationship will change to one of "mutual co-operation and trade".
Britain will give at least £33 million in aid to Darfur as part of a £67 million package of support for Sudan, the Department for International Development has announced.
The money will ensure 1.7 million people a year in Darfur have access to safe water and sanitation and 1.5 million people are given emergency food supplies, the Government said.
International Development Minister Lynne Featherstone said: "Our aid will help the poorest to get the help they need to stand on their own and make them better able to cope when crises occur."
An international donors conference is being held in Doha today for the development of Sudan's western region, which has been riven by violent conflict for a decade.
Almost half of Darfur's population depend on emergency relief and nearly two million remain displaced since the conflict began in 2003.
Sir Malcolm Bruce, chairman of the Commons International Development select committee, says UK tax payers cannot be expected to fund aid to Pakistan if the country's wealthy do not pay "meaningful" amounts of income tax.
The Government plans to increase its £267 million bilateral aid programme in Pakistan, which has one of the smallest tax bases in the world, for the financial year that ends today to £446 million in 2014/15.
During their inquiry into UK aid to Pakistan, MPs from the Commons International Development select committee were told that while one in three people in Pakistan live on less than 30p a day around 70 percent of the nation's MPs do not file a tax return.
The committee indicated it wants Prime Minister David Cameron to push for action on corruption and tax evasion with Pakistan's leadership and called for the Government to use its influence within the International Monetary Fund to press for urgent reform of the tax system.
Britain must only go ahead with a major increase in aid to Pakistan if the nation increases the amount of tax it collects from its own wealthy people, a Commons committee has recommended.
Pakistan will become the largest recipient of UK aid next year, a controversial move given the backdrop of corruption, tax avoidance and political instability, MPs warned.
Although there is a "powerful case" for continuing aid to the nation, British taxpayers must not be left to foot the growing bill unless Pakistan's wealthy are made to pay their fair share, the Commons International Development select committee said
"Any increase in the UK's official development assistance to Pakistan must be conditional on Pakistan increasing its tax collection and widening the tax base," its report states.
"We cannot expect the people in the UK to pay taxes to improve education and health in Pakistan if the Pakistan elite is not paying income tax."
David Cameron has paved the way for hundreds of millions of pounds from Britain's aid budget to be diverted to defence.
The Prime Minister hinted that the money could be spent on peacekeeping operations instead as he tried to placate some backbenchers who are angry at how much the country spends.