A swarm of hundreds of deadly hornets attacked and killed an American father and son enjoying a zipline experience on a holiday in Laos.

Daniel Owen, 47, and Cooper, 15, died on October 15 after being stung by hundreds of Asian giant hornets while they were on a zipline at a resort, The Sun reported.

The family were stung by Asian hornets (Vespa velutina), which have stings that can cause severe pain and the potential for a deadly allergic reaction.

The hornet attack happened as they were descending from a tree, The Times reported.

Asian hornets have strong stings that can cause painful and potentially deadly allergic reactions. Photo / Getty Images

Phanomsay Phakan, a doctor at the Phakan Arocavet Clinic where the pair were first taken, said their whole bodies were covered in red spots.

“It was very, very painful,” Phakan said.

“A lot of stings, more than one hundred, over the whole body. I thought already that it’s a very dangerous situation because I had never seen it as bad as that.”

It is understood that Owen and his son were still breathing when they arrived at the clinic.

When they arrived, they also did not show any symptoms of anaphylactic shock, The Sun reported.

The father and son reportedly died a few hours later in a local hospital.

Owen was the director of one of the branches of Quality Schools International.

The non-profit international school organisation said Owen touched countless lives with his warmth, leadership and unwavering commitment to education during his time as a teacher.

In New Zealand, several yellow-legged hornet nests have been spotted in recent weeks.

There have been six confirmed detections to date, including four queens. Two of these were small nests, more than a kilometre apart, which suggests there are likely more in the Auckland region.

Yellow-legged hornets are aggressive predators and can become highly abundant.

They threaten people’s health, biodiversity and especially honey bees, RNZ reported.