Hardline southern separatists staged a general strike in the port city of Aden on Sunday and called for protests later in the day against a national dialogue that they are boycotting, activists said.
A six-hour general strike, mostly in schools and universities across Aden, paralysed the capital of the formerly independent South Yemen.
Activists said thousands of protesters are expected to gather later in the evening in Mualla district at a rally organised by radical factions of the separatist Southern Movement against the UN-backed national dialogue which begins on Monday in Sanaa and is to last for six months.
Qassem Askar, a leader of a hardline faction in the Southern Movement said that his group is mobilising the street to "express our rejection to the national dialogue in Sanaa, as some are trying to lure the people away from their real cause" -- independence of the south.
The talks, originally scheduled to start in mid-November, were delayed mainly due to the refusal of factions in the Southern Movement -- campaigning for autonomy or secession for the region -- to join the dialogue.
The dialogue aims to draft a new constitution and prepare for general elections in February 2014 after a two-year transition led by President Abdrabuh Mansur Hadi.
The dialogue should take place under a deal that eased former strongman Ali Abdullah Saleh out of office after an 11-month uprising against his 33-year rule.
Most factions have finally agreed to take part after months of negotiations and under UN pressure.
But the movement's hardliners led by South Yemen's former president Ali Salem al-Baid have insisted that negotiations be held between two independent states in the north and south.
"It is a conspiracy against us by the international and regional community," said Askar, who belongs to Baid's faction.
"Several people have not been informed that they were appointed to represent southerners in the talks and some have withdrawn. Others representing southerners are of northern origins," he told AFP.
Anti-unity songs blared from loudspeakers in Aden as dozens of cars patrolled the city urging residents to participate in the rally later Sunday.
Several anti-dialogue slogans and calls for the secession of the south were smeared on walls of many buildings, in addition to displaying of flags of the former South Yemen in parts of the city.
"We refuse to participate in the dialogue which insults and betrays the programme of the southern revolt," said the head of the Southern Movement Council in Mualla, Hussein Zein.
After North and South Yemen united in 1990, the south broke away in 1994. The secession triggered a short-lived civil war that ended with the region being overrun by northern troops.
In 2007, the Southern Movement emerged as a social protest movement of retired officials and soldiers. But it has gradually grown more radical in its demands.
In addition to Baid's faction, the dialogue is boycotted by the head of the Southern Movement's Supreme Council Hassan Baoum, the most powerful faction of the alliance.
The National Council for the People of the South led by Haidar Abu Bakr al-Attas, who lives in exile in the United Arab Emirates, and the National Democratic Coalition led by Khaled Baharun and Abdulrahman al-Jisri, are also boycotting the talks.