Foreign ministers from Morocco, Algeria and Mauritania along with the chief negotiator from the Polisario Front liberation movement joined United Nations envoy to the disputed region, former German president Horst Kohler, in a secret location "near Geneva".

The UN said the aim of the two-day talks was to take "a further step in the political process towards reaching a just, lasting, and mutually acceptable political solution, which will provide for the self-determination of the people of Western Sahara."

A first round of talks was held at the UN in Geneva last December after six years of stalemate, but did not yield any breakthrough.

The UN said the purpose of the new round "is for delegations to start approaching elements needed for building an enduring solution based on compromise."

"The meeting will also serve as an opportunity for the delegations to revisit regional issues and discuss how to build trust," it said in a statement.

After the talks, South Africa will host "a solidarity conference" on March 25 and 26 in Pretoria to push for a referendum on the status of Western Sahara.

The international community has long advocated that a referendum be held to decide the status of Western Sahara, a former Spanish colony on the western edge of the vast eponymous desert, stretching around 1,000 kilometres (600 miles) along the Atlantic coastline, a prime fishing region.

- Peacekeeping mission -

The Polisario fought a war with Morocco from 1975 to 1991, when a ceasefire deal was agreed and a UN peace mission was deployed to monitor the truce.

The Polisario is demanding a referendum on independence, which Morocco has flatly rejected.

Morocco, which annexed the territory after Spain withdrew in 1975, considers Western Sahara an integral part of the kingdom and has instead offered autonomy.

To prepare for the talks, Kohler met bilaterally with all sides.

"He hopes that the meeting will consolidate the positive dynamic created by the first roundtable," the UN said.

The new round of talks comes as the mandate of the UN peacekeeping mission that has helped guarantee a ceasefire in Western Sahara since 1991 is about to end next month.

The United States has warned it may allow MINURSO's presence in Western Sahara to lapse, or it could agree to prolong its mandate by another six months.

Other Security Council members are pushing for a longer engagement, including France which wants the mandate extended for a year.