The UN refugee agency has said some 123,000 Rohingya refugees have fled to Bangladesh since violence erupted in Burma on August 25.
UNHCR spokeswoman Vivian Tan said today that the latest number is a result of aid workers carrying out new, more accurate counts in both established and makeshift refugee camps.
Yesterday, the agency had estimated that 87,000 refugees had crossed the swampy border in the days since Rohingya insurgents attacked Burma police posts, prompting security forces to launch "clearance operations" in response.
Ms Tan said "the numbers are very worrying. They are going up very quickly."
The older, established refugee camps for Rohingya have already reached capacity, and thousands are struggling to find shelter.