BOISE, Idaho (AP) — Idaho's newest prison, a 432-bed facility for drug and alcohol treatment, will likely open four months later than initially intended because the Department of Correction's nearly $169 million budget set Friday doesn't include enough money to staff it.

The $50 million lockup in the sagebrush desert south of Boise was supposed to open in May amid a sprawling complex of prisons built since the 1970s.

The opening, however, was first delayed until June and now will likely be pushed back even further to September.

The agency's spending plan is virtually unchanged from the current year but is $30 million less than two years ago, as the poor economy shrinks state spending while the prison population increases.

Last June, Idaho prisons had about 7,250 inmates. The population stood at 7,422 inmates on Friday, meaning 100 percent of cells were filled. Another 365 prisoners were being kept at county jails across Idaho.

Including people on parole or probation, the agency manages more than 20,000 offenders.

"We're in a very difficult financial situation in the state, and this budget, like all the other budgets, will be difficult to work through," Rep. Darrell Bolz, R-Caldwell, said.

The prison agency's spending plan still must be approved by the state House and Senate.

By opening the drug prison, known at the Correctional Alternative Placement Prison, Idaho had hoped to vacate a converted warehouse south of Boise that houses 300 inmates on the site of the Idaho State Correctional Institution.

Trouble erupted at the warehouse in January 2009, when prisoners unhappy with their makeshift accommodations broke control-room windows, overturned furniture and started a small fire.

The facility will remain open, at least for the time being, at an annual cost of about $1 million, while the new drug prison remains empty.

Sen. Nicole LeFavour, D-Boise, argued that prisoners will be deprived of treatment opportunities critical for kicking drug habits and returning to normal life.

"One of the greatest obstacles to getting people through the corrections facilities on time and ready for release is a lack of treatment in the facilities, as they exist," LeFavour said. "A lack of investment in this particular area is probably going to cost us in the long run."

Department of Correction Director Brent Reinke said he's in negotiations with Management & Training Corp., a Centerville, Utah-based prison management company, to delay hiring staff for the new facility.

Reinke has cut 44 jobs in the current year and demanded the agency's 1,500 workers take 44,000 furlough hours.

He is concerned the state prison population will grow more rapidly amid budgets challenges for drug and mental health treatment by the Department of Health and Welfare.

"The bottom line is, people are going to continue coming to prison for substance-abuse treatment," Reinke said.

There are currently no plans to release inmates early, as California and Oregon have tried to help remedy budget shortfalls.