Japan's first privately built prison has begun accepting inmates as the nation desperately seeks to relieve overcrowding behind bars, officials have said.

The prison has hundreds of single rooms, each equipped with a bed, TV and safe. It has career programs, and there is no barbed wire — making it luxurious in comparison with other Japanese prisons.

The prison officially opened May 13 in the town of Mine in Yamaguchi Prefecture. It will only accept up to 1,000 first-time prisoners, men and women, who are serving terms of 8 years or shorter.

The new prison, called the Mine Social Reintegration Promotion Center, uses orange or green uniforms instead of the standard gray, pajamalike suits used elsewhere.

The prison had accepted "several dozen" inmates by Friday, said Justice Ministry official Takao Hosokawa, who said the number rises almost daily.

"Our primary goal is to relieve the overcrowding at prisons. We have taken various measures, but those cosmetic changes had their limits," Hosokawa said.

Japanese prisons have become crowded amid an increase in serious crimes and a trend toward tougher sentences. The inmate population had exceeded 72,100 by the end of March, with man facilities filled to more than 110 percent of capacity.

Many prisons have packed more inmates into each room while others have turned offices into makeshift cells.

Like other prisons, the government runs security and the correctional and career programs at the new Mine Social Reintegration Promotion Center. But it has also adopted proposals from the private consortium, which includes a major security firm, and has signed a 51.7 billion yen, 20-year contract allowing the government to save 4.8 billion yen.