Four children have been found alive in the Amazon jungle 40 days after the plane they were travelling in crashed, killing their mother and two pilots.

After a huge search, the siblings were rescued by the military in the Colombian jungle, close to where the small plane had crashed.

For more than a month the children — aged 13, nine, four and one — fended for themselves in the dense and wild rainforest.

Their Cessna 206 was carrying seven people when it issued a mayday alert due to engine failure in the early hours of May 1.

Miraculously the children survived the impact.

Three bodies were found inside the plane.

Narcizo Mucutuy, the grandfather of the three girls and one boy, told reporters he was delighted at news of their rescue.

“As the grandfather to my grandchildren who disappeared in the jungles of the Yari, at this moment I am very happy,” he said.

‘Joy for the whole country!’

Photos shared by Colombia’s military showed a group of soldiers with the four children in the middle of the jungle.

Colombia’s President Gustavo Petro said it was a “magical day”.

“A joy for the whole country! The four children who were lost … in the Colombian jungle appeared alive,” Mr Petro said via Twitter.

“They were alone, they themselves achieved an example of total survival which will remain in history.”

Mr Petro initially reported the children had been found on May 17 in a message on Twitter but later deleted the post, saying the information was unconfirmed.

“They were together, they are weak, let’s let the doctors assess them,” Petro told journalists, adding the children had defended themselves alone in the middle of the jungle.

“They found them — it makes me very happy.”

Rescuers, supported by search dogs, had previously found discarded fruit the children ate to survive, as well as improvised shelters made with jungle vegetation.

Airplanes and helicopters from Colombia’s army and air force participated in the rescue operations.

-AAP