The call from the United Nations high commissioner for refugees follows an earlier appeal to developed countries to grant a new home to 30,000 of the most vulnerable Syrians driven from their country.
With no sign of an end to the brutal three-year conflict between the regime of Bashar al-Assad and rebel forces, tens of thousands more will need help in the near future, it said.
"UNHCR anticipates that in the coming years, there will be increasing numbers of vulnerable Syrian refugees who will be in need of resettlement, relocation, or other forms of humanitarian admission," said spokesman Dan McNorton.
The agency said it aimed to find a haven for the 100,000 new refugees during 2015 and 2016.
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But it is still working to place the initial 30,000 before the end of this year.
Twenty countries have so offered more than 18,800 slots for resettlement or a long-term temporary permit.
Germany has done the most to shoulder the load, agreeing to take in 10,000 on a federal programme and 1,500 under schemes in individual states.
Canada has pledged 1,300, Sweden 1,200, Norway 1,000, and countries including Australia, Austria, Finland and France have agreed to take in 500 each.
The figures are a shadow of the number of Syrian refugees in the Middle East.
All told, there are some 2.4 million Syrians spread across the region.