A representational image showing a coral reef. Reuters/File

Scientists have discovered the largest coral ever recorded in the south west Pacific Ocean and described it to be bigger than a blue whale.

The mega coral, a combination of several connected tiny creatures that together form one organism rather than a reef, is likely to be over 300 years old, according to BBC.

A videographer working on a National Geographic ship visiting remote parts of the Pacific found it. The person wanted to see how it has been impacted by climate change.

“I went diving in a place where the map said there was a shipwreck and then I saw something,” said Manu San Felix.

Moreover, he called over his diving buddy, who is also his son Inigo, and they dived further down to inspect it.

Seeing the coral, which is in the Solomon Islands, was like seeing a "cathedral underwater", he said.

"It's very emotional. I felt this huge respect for something that's stayed in one place and survived for hundreds of years," he said.

By using a type of tape measure under water, scientists on the expedition measured the coral. It was found to be 34m wide, 32m long and 5.5m high.

As oceans warm with climate change, corals are facing severe pressures globally.

Corals, often described as an “architect” of the seas, can join together to form vast reefs where fish and other species live.

Additionally, according to the World Economic Forum, coral reefs also underpin the livelihoods of one billion people including by supporting tourism or fishing.