|Turabi, once Bashir's mentor but now a critic, says that the opposition will overthrow the government [Al Jazeera]
Hassan al-Turabi, the Sudanese opposition leader, once seen as the real power in his country, has said that opposition parties are working on peaceful ways to overthrow the government of president Omar al-Bashir.
"As dialogue with the regime took a long time, and after opposition leaders realised that the elections were hopeless... they have agreed to topple the regime," Turabi, once Bashir's mentor but now one of his fiercest critics, said on Monday.
"Sub-committees have been designated to prepare... the means by which to overthrow the regime right after the results of the referendum are announced," added Turabi of the upcoming vote on independence for south Sudan.
Al Jazeera's Omar al-Saleh, reporting from Khartoum, said the government was facing a lot of opposition calls to be toppled.
"The Popular National Congress Party led by Hassan al-Turabi, the Ummah Party led by Sadiq al-Mahdi and other parties in Sudan are calling for the government to step down after the referendum," he said.
"They threatened that they will take to the streets to do so - there is no talk about violence in this process and they said that the means will be peaceful."
Voting on independence is due to begin on Sunday, with the result expected to be overwhelmingly in favour of secession.
Turabi said the opposition leaders have agreed that a change of government will come "not with weapons but with the people."
"The upcoming outburst of the Sudanese people will not happen only in Khartoum, but in all of Sudan," he said.
"Civil society has the ability to overthrow the regime peacefully," said Turabi, who was arrested and jailed last year after criticising April elections which returned Bashir to power.
"Opposition leaders here in Khartoum have called on their supporters to go down to the streets, trying to topple the government of president al-Bashir," our correspondent said.
"But the government, and president Bashir himself, have warned the opposition from taking to the streets or they all will be arrested."
Sudan's first multi-party elections since 1986 were marred by complaints from the opposition and foreign monitors, as well as by accusations of fraud.
Turabi said on Monday the opposition move "will either force the ruling authorities to make concessions or will make the national opposition movement push the people to a rebellion."
He dismissed talk of a coup, saying that "all the Sudanese people now hate" such an option. Bashir himself came to power in a bloodless coup.
Turabi expressed confidence that south Sudan would choose secession in the referendum, warning of similar secessionist tendencies in other regions.
"The south will undoubtedly become independent," he said, but ruled out the possibility of a north-south war. "Maybe Darfur and the east will follow."
North and south Sudan signed a peace deal in 2005 after a devastating 22-year civil war. It included provision for a referendum on southern independence.
Almost four million people have signed up to vote in the referendum, organisers said on Monday.