UN envoy to Yemen Jamal Benomar will meet leaders from the Southern Movement, a separatist group, ahead of a national dialogue that some of them aim to boycott, an aide said said in Dubai on Friday.
"Mr Benomar meets Southern Movement leaders in Dubai on Saturday as part of consultations with all Yemeni parties" before a national dialogue is to begin on March 18, Abderrahim Saber said.
Saber said various factions of the movement, including that of secessionist Ali Salem al-Baid, have "confirmed their presence for the meeting."
"Two representatives of Mr Baid are expected to attend the meeting," he said, adding that "some leaders from within (Yemen) like Hassen Baum, have not had time to get visas.
"Hassan Baum, head of the Supreme Council of the Southern Movement, is among 25 southern personalities invited by Mr Benomar to Dubai but can't leave Sanaa without visas," Fuad Rashid, an aide to Baum told AFP.
He accused the authorities in Sanaa of "derailing the meeting in Dubai."
The southern question is part of the agenda of the national dialogue.
"The dialogue will be open to all. Even those who want to discuss secession are welcome. The sole condition is that the dialogue be peaceful" to prepare for the next phase of the political transition in Yemen," an adviser to Benomar said.
The dialogue, originally scheduled in mid-November, aims to draft a new constitution and prepare for elections in February 2014 after a two-year transition following the departure of former president Ali Abdullah Saleh.
Saleh stepped down last year following massive street protests.