Kazuhiro Ogawa, 46, admitted he set fire to newspapers in the middle of the night in a tiny room of the Cats video parlour, which offers adult films and other entertainment for people who need a cheap place to stay.

'I was sick and tired of living,' Ogawa told investigators, according to police in the western Japanese city.

Ogawa brought the newspapers with him in a bag with a plan to set them alight 'knowing that the act could result in the deaths of customers,' an Osaka prefectural police spokesman told AFP.

Despite his wish to die, Ogawa survived with no apparent injuries, although his booth in the ground-floor video parlour was more scorched than others, officials said.

More than 40 fire engines rushed to the scene after an emergency call at 3am (2am Singapore time). The shop in the packed Namba entertainment district offered 32 small private rooms.

'Fifteen people, all men, died. All of them are believed to be customers of the video shop,' fire control centre official Takashi Ishida said.

Ten other people - nine men including those on other floors of the building and a woman in an adjacent building - were injured in the blaze, he said. Four of them were seriously hurt.

Police in Osaka were questioning one of the surviving customers of the video establishment who said he was smoking before falling asleep in one of the rooms, Japanese media said.

'I smelled burning wood or something like matches when I woke up,' a survivor told local television. 'When I opened the door, the lights were off and smoke was all over the place.'

Some 40 fire engines and other units were dispatched to fight the blaze, which was contained on the ground floor, reports said. Most people reportedly died of smoke inhalation.

Another customer told Jiji Press that there were no emergency lights or exits and that no staff helped them rush out of the store, which had a complicated layout.

'I'm afraid those who were in a deep sleep might have been too late to escape,' the man said. 'I'm glad I was able to escape.'

The deadly fire in a night-life area was a grim reminder of a 2001 building fire in Tokyo that killed more than 40 people, including bar hostesses and their customers.

The fire in the capital's Kabukicho red light district led to a toughening of fire safety laws.

Fire officials said their inspection of the Osaka video shop did not result in any citations.

The website for the Cat's shop said it offered a wide selection of DVDs and brought in new adult films every week. The small rooms included a sofa-bed and a television.

The website said the shop was aimed at customers 'from those who want to watch DVDs in a relaxed manner to those who missed their last trains.' Major Japanese cities are full of establishments designed for people who stay out working or partying after the public transport systems shut down, as taxi rides can be prohibitively expensive.

The Cat's shop said it charged 1,500 yen (S$20) for an overnight stay from 11 pm through 10 am - much cheaper than hotels in central Osaka.

Japan has also been alarmed by the rising number of young people who have virtually moved into all-night lounges offering videos and comic books as their jobs do not pay well enough for them to afford proper housing.

A labour ministry survey last year said that Japan, the world's second largest economy, had about 5,400 'Internet cafe refugees'. -- AFP