United Nations chief Ban Ki-moon said Saturday that saving the lives of migrants stranded at sea in Southeast Asia should be a "top priority" as the region battles with an exodus of boat people fleeing persecution and poverty.

The UN Secretary General said he hoped regional nations would tackle the "root causes" of the current exodus at an upcoming conference in Thailand later this month.

"But when people are drifting on the sea, how we can search and rescue them and provide life saving humanitarian assistance, that is a top priority at this time," he told reporters during a visit to Hanoi.