Mr Turabi announced his plans to step down several weeks ago following the passage of a new law that restores the country's multi-party system.

Sudan is run by an Islamic-backed military regime, which seized power from the country's civilian politicians in 1989.

Mr Turabi: Speaker since 1996

"I am announcing to you my resignation as speaker of parliament. I will remain amongst you as a member, leaving this seat for someone else," Mr Turabi said in a speech in the National Assembly.

Mr Turabi now plans to devote himself to the political future of the governing National Congress, of which he is already secretary-general.

The Political Associations Law, which is expected to come into effect on 1 January, 1999, paves the way for elections in which other political organisations are to be allowed to contest seats.

Full circle

Our correspondent in the region, Barbara Plett, says the ideologue will have come full circle when he registers the National Congress in the New Year.

It was under his guidance that military ruler General Omar al-Bashir banned parties in the coup nine years ago.

The new legislation avoids using the word "party". But it allows political associations to contest elections as long as they uphold a new constitution that enshrines Islamic law.

Observers say Sudan is likely to develop a dominant party system controlled by the National Congress.

Opposition fear divide and rule

Exiled opposition leaders have already dismissed the government's moves to reinstate political pluralism.

The Umma Party of former Prime Minister Sadeq al-Mahdi and the Democratic Unionist Party say they will not register their parties under the new law.

They say the only way to restore true democracy in Sudan is to form a transitional government of national unity and convene a new constitutional conference that includes all political forces.

They fear the authorities will try and divide the traditional parties by granting licences to alienated members.