The UN refugee agency says roughly 400 people a day, about 20 times the previous rate, are now crossing from Sudan into eastern Chad.
Daily arrivals have surged past 400 in the past week as fighting and insecurity worsen in Sudan, according to Anadolu Agency, citing the UN refugee agency.
The funding targets people displaced by the latest military escalation in the country, the UN refugee agency said.
The UN refugee agency warns Djibouti's reception capacity is "rapidly diminishing" as more than half of new arrivals are women and children.