At least 10 people have died in a fire in a Cambodian hotel-casino on the border of Thailand, Cambodian police said on Thursday.

A provisional Cambodian police report seen by AFP said the fire broke out at the Grand Diamond City hotel-casino in Poipet about 11.30pm local time on Wednesday.

"About 10 people died and 30 [were] people injured," the report said.

It was reported the fire began when a gas tank exploded on the casino side of the complex.

The blaze continued into Thursday morning.

Reuters reported at 11.16am that Cambodian police said the fire was finally under control.

Emergency crews from the provincial and national government were sent to assist. Crews were reported to have reached the upper floors and were using crowbars to gain access to individual rooms.

Witnesses said they heard a series of explosions from the ground-floor kitchen of the complex, which is opposite Rong Kluea market in Aranyaprathet district of Thailand's Sa Kaeo province.

At least one Thai was among those killed, with others injured, Sa Kaeo governor Parinya Phothisa said.

Dozens of people, many of them Thai employees and tourists, were reported trapped both inside and on the rooftop of the 17-storey complex, which included casinos on its first three floors and more than 100 luxury hotel rooms.

Fire crews and helicopters from Thailand were deployed to help fight the blaze and evacuate the premises. 

Injured people were being rushed to hospitals in Aranyaprathet district. It was reported that emergency units were already overloaded in the border district.