KHARTOUM, Apr 6 - Sudan insisted on Tuesday that presidential, parliamentary and local elections would go ahead as planned on April 11-13, despite a threat by several opposition groups to boycott the vote.

There will be "no delay," Hadi Mohammed, head of the technical committee of the National Elections Commission, told reporters after talks with US special envoy to Sudan Scott Gration.

"Preparations are finished," he said.

Gration said Saturday after meeting members of the electoral commission that he was confident the elections would be as "free and fair as possible" and would start on time.

Sunday's polls, Sudan's first general election since 1986, has been marred by the withdrawal of President Omar al-Beshir's main challenger Yasser Arman, and by the boycott of several opposition groups.

With no strong challenger Beshir, who is wanted by the International Criminal Court for war crimes and crimes against humanity committed in Darfur, looks set for a comfortable win.

Local and legislative elections are by contrast fiercely competitive.