The siblings of kidnapped Australian man Warren Rodwell, held hostage for 15 months in the Philippines, say they're relieved he's finally been released after a difficult and exhausting ordeal.

Mr Rodwell's sister Denise Cappello and brother Wayne Rodwell have thanked Philippine and Australian authorities for helping secure their younger brother's release from the hands of al-Qaeda-linked group Abu Sayyaf.

"We're happy and relieved that Warren has finally been released," Ms Cappello told reporters in Manila on Monday.

"He is delighted to be free. He has however lost a lot of weight and is exhausted."

Ms Cappello wished the Philippine national police success in tracking down and capturing Mr Rodwell's abductors.

"We hope they are brought to justice so others don't have to experience what Warren has just been through," she said.