Abdullah Ensour made the link between refugee admissions and aid in unusually blunt comments today, during a visit to the Azraq refugee camp.
He spoke ahead of next week's Syria conference where pledges of some USD 9 billion are being sought for 2016 to alleviate the fallout from the five-year-old civil war.
The conflict has uprooted millions of Syrians, including more than 4 million who fled their homeland.
Most live in overburdened regional host countries such as Jordan, which has taken in about 630,000.
The upcoming aid conference in London will try to find ways to keep more refugees in the region, including by putting large numbers to work and making them less dependent on aid.
Currently, most refugees are not allowed to work legally in Jordan and Lebanon, which face high domestic unemployment.
Ensour today warned of possible changes in Jordan's refugee policy. "We have opened our borders," he said.
"We will continue to do so provided that others come and help us help the Syrians ... I don't mean just sending cash or grants.
If such support is not received, "then it would be very, very difficult for us to continue the way that we did in the past," he added.
Jordan and Lebanon have already tightened entry restrictions for refugees in recent months.
About 17,000 Syrians, including women and children, are stranded in rough conditions in a remote desert area on the Jordanian border, many already waiting for months to enter the kingdom.
International aid agencies have called on Jordan to speed up security checks and move refugees to the Azraq camp, which stands largely empty.
