The open letter to David Cameron comes ahead of the first anniversary on Thursday of the UK government's announcement of a special resettlement scheme for the most vulnerable refugees from the Syrian conflict.
A year on, Home Office figures show that only 90 people have been offered asylum in Britain.
Nearly four years into the conflict, ten million people have been forced to leave their homes, nearly four million of whom have fled the country, according to Christian Aid.
The charity says the vast majority are living in precarious circumstances in Syria's neighbouring countries, and many are struggling to survive in freezing temperatures.
Faith leaders, including the Archbishop of Wales Dr Barry Morgan, the Head of the Jewish Reform Movement Rabbi Laura Janner-Klausner, Bishop Declan Lang, Chair of the Bishops' Conference Department of International Affairs and Shaykh Ibrahim Mogra,Assistant Secretary General of the Muslim Council of Britain and Co-Chair of the Christian Muslim Forum have expressed their support for a joint call from Amnesty International, Christian Aid, the Refugee Council, JCore, Islamic Relief and Cafod for the UK to do more to help Syria's refugees find safety here.
In their letter they write: "Many refugees have experienced persecution, torture or sexual violence, sometimes because of their religion or ethnicity, or have disabilities or other urgent medical needs which make them particularly vulnerable. Some will not survive the winter.
"We are proud of the way in which the UK has led the world in its humanitarian aid contribution to the Syria crisis. However, our help cannot end with aid. We urge you to show the same leadership on resettlement so that more of Syria's most vulnerable refugees can find sanctuary here in the UK.
"We welcomed the announcement, a year ago, of the Syrian Vulnerable Persons Relocation (VPR) scheme but we are disappointed that only 90 refugees have so far been offered a safe haven here in the UK via this route. One year on, we urge you to take this opportunity to commit to offering resettlement places to thousands, not hundreds, of refugees from Syria.
"In the face of a desperate and growing need, we believe that Great Britain has a moral responsibility to continue our noble tradition as a compassionate and welcoming safe haven for those in need of protection. As Prime Minister, you have the power to offer hope to people whose suffering is almost unimaginable to us. We ask you to do this today."
Amnesty International is calling on rich countries around the world to resettle five per cent of Syria's refugees by the end of this year and a further five per cent by the end of 2016. The UK government has agreed to resettle only several hundred people over three years.
Other countries, including Germany and the USA, have promised to resettle thousands.
Excluding Germany, the rest of the European Union (EU) has pledged to take 0.17 per cent of refugees from the main host countries.