By Ruma Paul

DHAKA (Reuters) - A blaze swept through a Rohingya refugee camp in southeastern Bangladesh on Tuesday, killing a six-year-old boy and leaving about 2,000 people homeless in the sixth fire this year to hit the world's biggest refugee camp, officials and witnesses said.

The fire gutted parts of the Kutupalong camp in Cox's Bazar, a border district where than a million mostly Muslim Rohingya refugees live, most having fled a military-led crackdown in neighbouring Myanmar in 2017.

The blaze follows a massive fire in January, which destroyed 1,200 shelters and left more than 5,000 people homeless and four smaller fires between January and March.

Save the Children said some of the homeless families were staying with relatives, while others had been taken to other camps.

"The shelters made of dry bamboo and tarpaulin are incredibly flammable. More fire-resistant materials must be permitted and additional openings in the fencing need to be built so that refugees can reach safety in an emergency," Save the Children's Country Director in Bangladesh, Onno van Manen, said in a statement.

"The risk of fires in these densely populated and confined areas is enormous, but it is avoidable with the right support and infrastructure in place."

Mohammed Shamsud Douza, a Bangladesh government official in charge of refugees, said emergency workers had brought the fire under control after several hours. The cause was not immediately clear, he added.

"Unfortunately, one child died. And more than 300 houses were burnt in the fire," Douza told Reuters by telephone.

Video and photographs showed black smoke billowing over burning shanties and tents as people scrambled to recover their possessions.

"Everything burnt to ashes. Many are without homes," said refugee Mohammed Shafiullah.

A devastating fire last March swept through another refugee settlement in Cox's Bazar, killing at least 15 refugees and destroying more than 10,000 shanty huts.

(Editing by Nick Macfie)