South Korea is expecting to receive more than 300 North Korean refugees from an unnamed third country, press reports from Seoul say.
North Korean refugees often leave through China
The defectors apparently escaped through China to what is only described as "a South East Asian country".
Seoul stepped in when the country threatened to return them to China, says a South Korean civic leader.
The South has been accepting more than 1,000 people a year from poverty and hunger-stricken North Korea.
If the group arrives, it will be the largest single batch of refugees from the North.
South Korea's Yonhap news agency cited a diplomatic source saying Seoul was expecting between 300 and 400 people. One newspaper said there were more than 400.
The foreign ministry declined to comment on the reports.
Government and civic officials told the Kyunghyang Shinmun paper they have been trying to arrange the transfer since May, after the country hosting them complained.
The leader of a civic group, Chun Ki-won, told Reuters news agency the refugees had "simply created a big backlog for that country".
He said he did not want to name the country in case it jeopardised the deal being struck.
South Korea has accepted an increasing number of refugees from its northern neighbour in recent years, including 760 from the first six months of this year, according to official figures.
The South Korean government puts them in a halfway house before resettlement.