Phillip Mehrtens was captured by separatist rebels the West Papua Liberation Army after he landed a commercial plane on 7 February last year.

He was due to pick up 15 construction workers who had been threatened with death while building a health centre in the remote Nduga district.

Indonesian police said the pilot was freed on Saturday, 19 months after he was first captured, and is currently undergoing medical examination.

New Zealand foreign minister Winston Peters said "We are pleased and relieved to confirm that Phillip Mehrtens is safe and well and has been able to talk with his family. This news must be an enormous relief for his friends and loved ones."

The West Papua Liberation Army held Mr Mehrtens in a bid to open independence talks with the Indonesian government. His passengers were released because they were Papuans, rebel spokesman Sebby Sambom said at the time.

In May last year, a video showed the pilot looking emaciated and holding the banned Morning Star flag - a symbol of Papuan independence - while surrounded by armed rebels.

He said at the time the rebels wanted other countries to be involved in independence talks, and added that if "it does not happen within two months, then they say they will shoot me".

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Papua became part of Indonesia in a controversial 1969 vote and there has been an insurgency ever since, with frequent violence between indigenous people and security forces.

In more recent years, the fighters have been able to access better weapons, increasing the number of clashes.