The death toll from a massive fire that ripped through a Thai nightclub rose to 15 on Saturday, a rescue service said.

The fire broke out around 1:00 am (1800 GMT Thursday) at the Mountain B nightspot in Chonburi province's Sattahip district, about 150 kilometres (90 miles) southeast of Bangkok.

The Sawang Rojanathammasathan Rescue Foundation said Saturday that another man had died, taking the death toll to 15.

Most of the others who died -- four women and 10 men -- were found crowded by the entrance and in the bathroom, their bodies severely burned, the service said.

They were aged between 17 and 49. All are believed to be Thai.

Some relatives of the victims have travelled to Bangkok to retrieve the bodies of their loved ones after examination by forensic experts.

Flammable acoustic foam on the walls of the club accelerated the blaze and it took firefighters more than three hours to bring it under control, the rescue service said Friday.

Prime Minister Prayut Chan-O-Cha has ordered an investigation into the tragedy.

Police said Friday they were investigating reports some of the doors at the nightclub were locked at the time of the blaze.