(Updates refugee figures, adds background)
GENEVA, Jan 29 (Reuters) - More than 700,000 Syrian refugees have fled to other countries in the region and aid workers are struggling to keep up with the exodus, the United Nations said on Tuesday.
The number of refugees passed the 500,000 mark on Dec 11, meaning more than 200,000 have fled the war-torn country in the past seven weeks.
"We have seen an unrelenting flow of refugees across all borders. We are running double shifts to register people," Sybella Wilkes, spokeswoman for the U.N. High Commissioner for Refugees (UNHCR), told Reuters in Geneva.
A total of about 712,000 refugees had registered in other countries in the region or were awaiting processing there as of Tuesday, according to UNHCR figures.
Jordan has 171,033 registered Syrian refugees, as well as 51,729 who await processing, many of who fled fighting around the southern Syrian town of Deraa this month. Lebanon has 158,973 Syrian refugees, and 69,963 awaiting processing.
"We are trying to clear a backlog of people because the numbers have gone up so dramatically (in Jordan and Lebanon)," Wilkes said.
The conflict in Syria, a revolt against President Bashar al-Assad, has lasted for almost two years. Rebels have pushed into major cities like Aleppo and Damascus and taken territory in the north and east, while government forces have bombarded rebel-held areas with artillery and air strikes.
Turkey has 163,161 Syrian refugees in its 15 camps while Iraq hosts 77,415, the UNHCR said. There are 14,375 in Egypt and 5,417 registered across the rest of North Africa.
"The needs are enormous, we can't get to everyone fast enough," Wilkes quoted Ninette Kelley, UNHCR representative in Lebanon, as saying on Tuesday.
The United Nations warned on Monday that it would not be able to help millions of Syrians affected by the fighting without more money.
It appealed for donations at an aid conference this week in Kuwait to meet its $1.5 billion target. It has received just 3 percent of that so far.
U.N. refugee chief Antonio Guterres will attend the talks. The UNHCR and its partners are seeking $1 billion for Syrian refugees out of the $1.5 billion sought by the United Nations and has received 18 percent of that total to date, Wilkes said.
(Reporting by Stephanie Nebehay; Editing by Pravin Char)