Journalist Peter Greste left Egypt for his native Australia on Sunday after being deported by the country, security sources said.
Greste, whose case has sparked international outcry, was released from a Cairo prison where he was held for
400 days on charges that included aiding a terrorist group.
His deportation took place under the observation of Interpol, an official source at the Cairo airport told Al-Ahram.
The Australian government has repeatedly called on Egypt to drop the charges against Greste.
Greste and two other Al Jazeera journalists – Canadian-Egyptian Mohamed Fahmy and Egyptian Baher Mohamed – were sentenced last June to between seven and ten years in jail for spreading false news and aiding the banned Muslim Brotherhood. They have been detained since December 2013.
Rights groups and Western governments have criticised the detentions. Al Jazeera has condemned the charges against its staff, saying the trial was flawed.
The High Court ordered a retrial of the reporters on 1 January, but no date has yet been set.
President Abdel-Fattah El-Sisi said in November that a presidential pardon was being studied but ruled out granting the journalists clemency until the legal process has been finalised.
The deportation decision was issued according to a law passed in late 2014 that allows foreign convicts to be transferred to their country to either be retried or serve their sentence.
Informed sources said that Fahmy, who also has Canadian nationality, will be deported to Canada soon. However, no information is yet confirmed concerning Fahmy or Mohamed.
Greste was released according to a presidential decree and after the approval of the cabinet, said the ministry of interior on its official Facebook page. The new law stipulates that the general prosecutor has to request the transfer of the prisoners and that the cabinet has to approve the request.
In an official statement, Al Jazeera network said that the campaign to release its journalists will not end with Greste’s deportation. “We will not rest until Baher and Mohamed also regain their freedom,” said Mostafa Souag, the acting director general of Al Jazeera network. “The Egyptian authorities have it in their power to finish this properly today, and this is exactly what they must do”.
Egyptian President Abdel Fattah El- Sisi has said on a number of occasions that he wished that the imprisoned Al Jazeera journalists had not been put on trial. He said that the best way to deal with violations committed by foreign journalists was to deport them. However, he made it clear that he could not interfere with the judicial process, stressing that the country's judiciary was "completely independent."
The Al Jazeera case is believed to have stemmed from strained ties between Cairo and Doha, which funds the Doha-based media organisation and was one of the main supporters of deposed Islamist president Mohamed Morsi and his Muslim Brotherhood group.
Cairo has accused Al Jazeera of being a mouthpiece for the now-outlawed Brotherhood, charges the channel denies.
A recent thaw in ties between Cairo and Doha offered fresh hope over the fate of the journalists.