BEIRUT, Lebanon — Syrian Kurdish parties are working on a plan to declare a federal region across much of northern Syria, several of their representatives said on Wednesday. They said their aim was to formalize the semiautonomous zone they have established during five years of war and to create a model for decentralized government throughout the country.

If they move ahead with the plan, they will be dipping a toe into the roiling waters of debate over two proposals to redraw the Middle East, each with major implications for Syria and its neighbors.

One is the longstanding aspiration of Kurds across the region to a state of their own or, failing that, greater autonomy in the countries where they are concentrated: Turkey, Iraq, Iran and Syria, all of which view such prospects with varying degrees of horror.

The other is the idea of settling the Syrian civil war by carving up the country, whether into rump states or, more likely, into some kind of federal system. The proposal for a federal system has lately been floated by former Obama administration officials and publicly considered by Secretary of State John Kerry, but rejected not only by the Syrian government but by much of the opposition as well.