WASHINGTON (Reuters) - The Justice Department plans to change how it prosecutes some non-violent drug offenders, so they would no longer face mandatory minimum prison sentences, in an overhaul of federal prison policy that Attorney General Eric Holder will unveil on Monday.

Holder will outline the status of a broad, ongoing project intended to improve Justice Department sentencing policies across the country in a speech to the American Bar Association in San Francisco.

"I have mandated a modification of the Justice Department's charging policies so that certain low-level, nonviolent drug offenders who have no ties to large-scale organizations, gangs, or cartels, will no longer be charged with offenses that impose draconian mandatory minimum sentences," Holder is expected to say, according to excerpts of his prepared remarks provided by the Justice Department.

The United States imprisons a higher percentage of its population than other large countries, largely because of anti-drug laws passed in the 1980s and 1990s.

Holder will also reveal a plan to create a slate of local guidelines to determine if cases should be subject to federal charges.

The attorney general will point to the bipartisan backing of such goals in Congress, where there is "legislation aimed at giving federal judges more discretion in applying mandatory minimums to certain drug offenders."

The bipartisan backing could be important because the Obama administration will need Republican support for any major changes in Congress.

Holder is expected to say that laws like these could save the United States billions of dollars.

The attorney general will also announce an updated plan for considering release for "inmates facing extraordinary or compelling circumstances - and who pose no threat to the public."

(Reporting by Gabriel Debenedetti; Editing by Eric Walsh)

Update: American Civil Liberties Union released a statement on Monday regarding the DOJ's new policy:

"Today, the attorney general is taking crucial steps to tackle our bloated federal mass incarceration crisis, and we are thrilled by these long-awaited developments," Laura W. Murphy, director of American Civil Liberties Union's Washington Legislative Office, said in a statement. "By mandating that U.S. attorneys change charging practices for low-level, non-violent offenders, these policies will make it more likely that wasteful and harmful federal prison overcrowding will end. Over the last year, in one of the few areas of bipartisanship, members of Congress have come together to call for smart criminal justice reform. While today's announcement is an important step toward a fairer justice system, Congress must change the laws that lock up hundreds of thousands of Americans unfairly and unnecessarily."