Philippine cop nabbed for 2011 kidnapping of Aussie man

A Philippine policeman who is a cousin of one of the nation's top Islamic militants has been arrested over the kidnapping-for-ransom of Australian Warren Rodwell.

Jun Malban went on the run after he was charged with kidnapping Rodwell from his home in a southern Philippine coastal town in December 2011.

He was detained in Malaysia early this month and deported back to the Philippines on Friday last week, national police anti-kidnapping unit head Senior Superintendent Roberto Fajardo told reporters.

The abductors, members of the Abu Sayyaf Islamic militant group with a long history of kidnappings for ransom, posed as policemen when they seized him and initially demanded $US2 million ($A2.5 million) for his release.

Rodwell was released 15 months later in return for a ransom that a local politician said was worth about $US100,000, although such a payment has never been officially acknowledged by the Philippine or Australian governments.

Fajardo said Malban was believed to have been working with Rodwell's kidnappers and brokered a ransom.

"Rodwell identified Malban as the negotiator of the Abu Sayyaf during his captivity," he said.

Malban, who had worked for a southern Philippine police unit that provides bodyguards to civilians under threat, is a cousin of Abu Sayyaf leader Khair Mundos, he said.

Mundos, who had a $US500,000 United States government reward on his head, was arrested in a rundown Muslim quarter near Manila airport in June last year. The US government described him as a "key leader and financier" of the Abu Sayyaf.

Founded in the 1990s with seed money from Osama bin Laden's al-Qaeda network, the Abu Sayyaf has gained international notoriety for kidnapping sprees that target locals and foreigners in the Muslim-majority southern Philippines.

The Philippines' lowly paid police force has an enduring reputation for corruption and it is not unusual for officers to be accused of involvement in kidnappings or other crimes related to earning more money.