A whale has died in southern Thailand after swallowing more than 80 plastic bags.

The small male pilot whale was found barely alive and vomited up five bags while rescuers battled to save it over four days, marine officials said.

A post-mortem examination revealed 80 plastic bags, weighing up to 1st 3lb, in the creature's stomach.

​Thon Thamrongnawasawat, a marine biologist, said the bags had made it impossible for the whale to eat any nutritional food.

"If you have 80 plastic bags in your stomach, you die," he said.

At least 300 marine animals, including pilot whales, sea turtles and dolphins, perish each year in Thai waters after ingesting plastic, he added.

"It's a huge problem. We use a lot of plastic."

Last year Ocean Conservancy found that Thailand is one of the world's top-five plastic polluters, alongside China, Indonesia, the Philippines and Vietnam.

Together these countries are responsible for more than half of the plastic that washes into the ocean annually – thought to be between eight and 13 million tonnes.

The pilot whale was found on Monday in a canal near the border with Malaysia, Thailand's Department of Marine and Coastal Resources said on Facebook.