The US state of California has been forced to release a 'significant' number of inmates from its overcrowded prisons due to mounting costs and a crippling budget deficit.

Presstv | Recently, California has been releasing a 'considerable' number of its 167,000 prisoners in the state's 33 prisons in an effort to slash spending and help fight a burgeoning 20 billion dollar budget deficit that has already taken its toll on education, healthcare and other public services in the Golden State.

Authorities have announced plans to lower the number of inmates by 6,500 in 2012, US media say.

The decision to reduce the prison population, which is seen as a significant change in the state's detention policies for the past 30 years, has sparked controversies, with opponents criticizing the scaling back of prison populations and demanding a tougher approach to the issue.

Proponents argue that the readjustment of California's precarious annual spending plan calls for the distribution of around 11 percent of the state budget, or roughly $8 billion, normally allocated to the penitentiaries.

The recent economic meltdown, which has hit California harder than any other US state, has forced it to decrease its high incarceration rates by releasing lesser offenders and changing the 'revolving door' phenomenon by lighter supervision of parolees.

Some prisoners might also be freed for completing drug and educational programs