A UN envoy is set to host an "initial round-table" in Geneva this week between Morocco and the Polisario Front in a bid to kick-start dialogue on the disputed Western Sahara region.

"It is time to open a new chapter in the political process", said UN envoy Horst Koehler in an October invitation letter.

Six years after direct talks broke down, the meeting is expected to take place on Wednesday and Thursday, with neighbouring Algeria and Mauritania also attending.

A former Spanish colony, phosphate-rich Western Sahara sits on the western edge of the vast eponymous desert, stretching around 1,000 kilometres (620 miles) along the fish-abundant Atlantic coastline.

When Spain withdrew from the North African territory in 1975, Rabat sent thousands of people across the border and claimed it was an integral part of Morocco.

The following year the Polisario Front declared Western Sahara the Sahrawi Arab Democratic Republic (SADR), with support from Algeria and Libya, and demanded a referendum on self-determination to resolve the dispute.

But as the stalemate continued, Morocco built razor-wire-topped concentric sand walls in the desert that still ring 80 percent of the territory it controls.

A 1991 ceasefire saw the UN deploy a peacekeeping mission which has perpetuated the line of control, but the international community has long intended a referendum be held to decide the territory's status.

Rabat currently rejects any vote in which independence is an option, arguing that only granting autonomy is on the table and that this is necessary for regional security.

Living in limbo

Awaiting a settlement, between 100,000 and 200,000 refugees live precariously in camps in western Algeria, near the city of Tindouf.

The last round of direct talks were launched by the UN in 2007 but got bogged down 2012, as the opposing sides proved unable to compromise over the territory's status and the proposed referendum.

Leading the diplomatic efforts since 2017, Koehler -- a former president of Germany -- has already met the key protagonists several times, albeit separately.

His efforts have paved the way for the Polisario, Morocco, Algeria and Mauritania to sit at the same table, even if the format has not been unanimously agreed.

Algeria wants to participate only as an "observer country", but Rabat considers it a "stakeholder" in the discussions, since Algiers is the Polisario's main backer.

A UN briefing note says the Geneva meeting represents "a first step... with the aim of reaching a just, lasting, and mutually acceptable solution which will provide for the self-determination of the people of Western Sahara".

But the itinerary remains vague, outlining the delegations will take "stock of recent developments, address regional issues, and discuss the next steps in the political process on Western Sahara".

According to one diplomatic source, the plan is not to put too much pressure on this first meeting.

Instead, it should be considered more of a "warming up" exercise aimed at "breaking the ice", especially given still-poor relations between Rabat and Algiers.

The situation remains "generally calm" along the line of control, despite tensions that resurfaced in early 2018, according to a UN report.

For the Polisario, a recent reduction in the UN peacekeepers' mandate from 12 months to six months is part of a "dynamic" created by Koehler's appointment.

The UN Security Council adopted a US-drafted resolution in October to renew the peacekeeping mission and throw its weight behind the planned talks.

But ahead of the Geneva meeting, all sides are sticking to their positions, even as they signal their goodwill.

While supporting a "durable" political solution marked by a "spirit of compromise", King Mohammed VI said in a recent speech that Morocco will not yield on its "territorial integrity", including control over Western Sahara.

Key Polisario official Mhamed Khadad told AFP ahead of attending the Geneva talks "everything can be negotiated except the inalienable and imprescriptible right of our people to self-determination."

Reflecting its status as the Polisario's main supporter, Algeria likewise speaks of this "inalienable and imprescriptible" right.

In a recent official statement, Algiers said it would head to Geneva favouring "frank and fair" direct negotiations between the Polisario and Morocco aimed at building a definitive solution.