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.