Kurdish-controlled areas of northern Syria are expected to declare a federal system imminently, Kurdish officials say, taking matters into their own hands after being excluded from talks in Geneva to resolve Syria's civil war.

Key points: Kurds announce federalism in Syria

Kurds announce federalism in Syria The move follows exclusion from UN talks

The move follows exclusion from UN talks Turkey rejects 'validity' of decision

The step aims to combine three Kurdish-led autonomous areas of northern Syria into a federal arrangement and will be sure to alarm neighbouring Turkey, which fears a growing Kurdish sway in Syria is fuelling separatism among its own minority Kurds.

A conference held in the Kurdish-controlled town of Rmeilan on Wednesday discussed a "Democratic Federal System for Rojava — Northern Syria", and ended with a decision to make the announcement at a news conference on Thursday.

Rojava is the Kurdish name for northern Syria.

Aldar Khalil, a Kurdish official and one of the organisers, said he anticipated the approval of a new system, and "democratic federalism" was the best one.

Conference participants also forecast a failure of UN-led talks which began in Geneva this week, in the absence of the Syrian Kurdish PYD party.

Syrian Kurds effectively control an uninterrupted stretch of 400 kilometres along the Syrian-Turkish border from the Euphrates river to the frontier with Iraq, where Iraqi Kurds have enjoyed autonomy since the early 1990s.

Turkey, whose conflict with the Kurdish PKK has escalated in recent months, said such federalism was not acceptable.

"Syria's national unity and territorial integrity is fundamental for us," a Turkish Foreign Ministry official said.

"Outside of this, unilateral decisions cannot have validity."

On Saturday, Syria's government in Damascus ruled out the idea of a federal system for the country, just days after a Russian official said that could be a possible model.

The PYD has been left out of the Geneva peace talks, in line with the wishes of Turkey, which sees it as an extension of the PKK group that is waging an insurgency in south-eastern Turkey.

The area of northern Syria controlled by the Syrian Kurdish YPG militia and groups fighting with it is growing with their advances against Islamic State militants over the last year.

Syrian Kurdish groups and their allies have already carved out three autonomous zones, or cantons, known as Jazeera, Kobani and Afrin.

Their capture of the town of Tel Abyad from Islamic State last year created territorial contiguity between the Jazeera and Kobani areas.

Reuters