Chinese prisons are as safe and stable as they have ever been in history, even as the number of inmates they house has increased steadily since 2005, senior officials said on Wednesday.

China is now holding 1.64 million prisoners in 681 prisons, places that employ 300,000 prison officers, Wu Aiying, Minister of Justice, said while making a report at a bimonthly session of the National People's Congress Standing Committee, China's top legislature.

The report also noted that the prisons have helped nearly 1.3 million convicts become literate and receive a basic education since 2008. About two thirds of the inmates received vocational training in their time behind bars.

That's "one of the reasons why we've managed to keep the rate of repeat offenses relatively low".

The ministry has issued a series of regulations meant to safeguard the rights of inmates. It has set food, sanitation, and clothing standards and outlawed physical punishment, bullying and humiliation in prisons, according to the report.

The ministry has also brought prisoners under a weekly schedule that requires them to set aside five days for labor, one day for study and one day for rest, Wu said.

More than two thirds of prisons, to ensure their security, have established emergency centers and warning systems.

Last year, a prison break drew national attention and raised questions about the management of prisons.

In September, Wang Zhenqing, a criminal who has been sentenced to serve 11 years in prison for theft, fled from a jail in North China's Hebei province and was caught nearly two weeks later. By that time, Wang had traveled 470 kilometers.

In March 2008, Xie Wanli, another prisoner, hijacked a truck crane at a jail in Hebei and rammed open anti-riot gates and two other gates before breaking through a wall.

Xie was later caught by police and sentenced to spend his life in jail.