Bashir Adam Rahma, head of the political bureau of al-Turabi's Popular Congress party, said on Thursday he was outside the party offices waiting to repossess the premises from the authorities who seized them in April 2004.
"It is a complete lifting of the ban and there is also another decree which sets Dr al-Turabi free," he added.
Deputy Secretary-General of the party Abd Allah Hasan Ahmad Ahmad told Aljazeera that the release was unconditional.
"The decision will allow al-Turabi to freely practise any activity inside and outside Sudan," he added
The news came as Sudan was celebrating the 1989 military coup which brought President Omar al-Bashir to power.
Speaking on the 16th anniversary of the National Salvation Revolution on Thursday, President Omar al-Bashir told parliament that Khartoum was about to release all political prisoners.
He added that it came within the framework of creating an open political space and democratic reforms that would allow all political forces to abide by the law as well as the peace agreement and constitution.
Al-Turabi was arrested in March
2004 for an alleged coup plot
Al-Turabi, 75, was arrested in March 2004 over government allegations of a coup attempt by sympathisers of ethnic minority rebels in the western region of Darfur.
He has been free for only six months since being released from three years of house arrest in 2003.
Later speaking to Aljazeera at his home in Khartoum, al-Turabi expressed dissatisfaction at the state of freedom in Sudan.
"I am not reassured about freedom, neither for myself nor for the Sudanese people. I did not fight for myself or for a (government) position, but for freedom to the people," he said.
"Freedom of the press is still curbed through censorship. Political parties are still banned. Public rallies, which have now spread all over the world, are banned. Liberties are forbidden and freedom has no place in the new constitution", he told Aljazeera after his release.
No deal struck
Al-Turabi also denied that any deal was struck for his release.
"No deal has been forged between us and the Sudanese government," he said.
Al-Turabi called upon all political forces to close ranks because Sudan in his opinion is in a crisis and no longer an independent state. "The country is incapable of defending its own security. This is why we have to host armies from neighbouring countries to keep us secure," he said.
Sudan is currently facing civil
conflicts on several fronts
He said: "Because our justice system cannot maintain justice for all the people, international justice comes to complement our system. We are in a crisis that needs our concerted efforts for a resolution."
Asked whether he wants the desired changes to happen through peaceful means, national reconciliation or otherwise, al-Turabi said: "National reconciliation has never been known in Sudan. It is simply some words uttered."
He continued: "The state of emergency have been lifted, but may need to be re-instated any time. The restrictions on imposing emergency laws have been eased in the newly drafted constitution, compared with the previous document."
Al-Turabi concluded: "We will be ruled through emergency laws as in all Arab countries. Only one party rules."