Mr Brennan and his Canadian colleague Amanda Lindhout were released on Wednesday after a ransom was paid. It was rumoured that the payment was $US1 million, but an anonymous Somali official said the figure was $US700,000.

"I did assist with some money," he told ABC 2 Television, adding that Australian Greens leader Bob Brown put in a substantial amount of money to help support the search. Senator Brown had to borrow the money, he said.

"The media sort of makes out as if I'm some type of hero, that's some sort of clap trap.

"I'm only a minor player. The family themselves ... have done the most incredible job to get the young couple out, quite amazing."

He said the Brennan family contracted a UK company to rescue Mr Brennan and Ms Lindhout, after the government couldn't get them released.

"Finally the family took the whole thing back and got some experts from the UK who are experts at this and then the experts said within 90 days we'll have them out, and within 90 days they did."

He said the Brennan family had sold some of their property to finance the search.

Mr Brennan and Ms Lindhout flew out of the Somali capital, Mogadishu, in a chartered plane to Kenya early yesterday.