Al-Jazeera journalist Peter Greste has said he will not rest until his colleagues are released from a Cairo prison where he spent 400 days.

Greste, a former BBC reporter, made the comment after he was released ( on 1 February). He is now travelling to Australia, his country of origin.

Speaking at a press conference in the Australian city of Brisbane, brother Andrew Greste said: "We want to acknowledge that Peter's two other colleagues are still there," AP reported.

His father Juris Greste said that they felt very deeply for those left behind.

Australia's Foreign Minister Julie Bishop said Greste had told her in a telephone conversation that he was eager to return to his family in Brisbane.

"He was immensely relieved and he was desperate to come home to Australia and reunite with his family," said Ms Bishop.

"From my discussion with him, he was very keen to be back on a beach and lying in the sun in Australia."

Australia's Prime Minister Tony Abbott expressed his gratitude toward Egyptian President Abdel-Fattah el-Sisi for Greste's release.

"As a former journalist myself, it would be remiss of me at such a gathering of journalists not to express my personal delight and our nation's relief at the overnight release of Peter Greste and to reiterate our support as a government and as a people for a free media and a free press," he said.

Greste was arrested in December 2013 together with two of his colleagues, Canadian/Egyptian Mohamed Fahmy and Egyptian Baher Mohamed, and charged with spreading false news and aiding the Muslim Brotherhood, an Egyptian organisation.

Greste and Fahmy were sentenced in June 2014 to seven years in prison, while Mohamed was sentenced to 10 years.