Hopes are running high in Sudan that US President Donald Trump will decide this week to lift Washington's sanctions on Khartoum, despite rights groups calling for the decades-old embargo to be maintained.

"The time is right for permanently lifting the sanctions on Sudan," senior Sudanese foreign ministry official Abdelghani Elnaim told AFP ahead of the end of a review period on Wednesday.

"We are counting on President Trump to take this courageous decision that will make not just the people of Sudan, but all of Africa, happy."

Washington imposed a complex set of economic sanctions on Sudan in 1997 for its alleged backing of Islamist militant groups. Al-Qaeda leader Osama bin Laden, who was killed in a US commando raid in Pakistan in 2011, was based in Khartoum from 1992 to 1996.

Washington also justified the embargo with accusations of scorched-earth tactics by Khartoum against ethnic minority rebels in war-torn Darfur.

Barack Obama eased the sanctions before leaving office in an attempt to improve ties with Sudan whose leader President Omar al-Bashir is accused of genocide charges related to the conflict in Darfur.

However, he made the permanent lifting of sanctions dependent on Khartoum's progress in five areas of concern during the six-month review period.

The concerns -- known as "five tracks" -- include improved access for aid groups in conflict areas, an end to support for rebels in neighbouring South Sudan, an end to hostilities in the conflict zones of Darfur, Blue Nile and South Kordofan, and counter-terrorism cooperation with US intelligence agencies.

Trump can lift the sanctions permanently, extend the review period or fully re-impose the embargo.