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:
Ordinarily, the UK government should have informed the government of South Africa through official diplomatic channels of their intentions and allowed for proper consultations to take place, and the modalities of the announcement agreed on.
We have a SA/UK Bilateral Forum which is scheduled for some time this year and the review of the SA/UK strategy which includes the (Official Development Aid) would take place there and decisions about how to move forward were expected to be discussed in that forum.
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".
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".
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.
There is a powerful case for maintaining the UK's bilateral aid to Pakistan. Britain enjoys a close relationship and has long established ties with Pakistan which has real poverty and serious security problems...But the committee is concerned that not enough tax is raised in Pakistan to fully finance improvements in the quality of life for poor people. In particular, we cannot expect people in the UK to pay taxes to improve education and health in Pakistan if the Pakistani elite does 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."
Britain can be proud of the quality of its overseas development work and Christian Aid fully supports the Government’s move towards the UN target of 0.7% of gross national income on overseas aid by the end of this year.
However, we would be deeply concerned about any moves to link aid with military spending in fragile states, not least because of the risk it can pose to aid workers on the ground. Aid diverted to ‘security, peacekeeping and demobilisation’ could have long term implications.
The blurring of the lines between military action and aid delivery could mean that aid workers become associated with those forces, meaning they are not only put at risk, but find it hard to gain the trust of the people they are trying to help.