JACKSON (AP) — After months of bickering over the budget, Mississippi lawmakers spent less than six hours in special session Friday to approve the final details of the state’s $6 billion spending plan.

The House and Senate approved budgets for the Public Service Commission and the related Public Utilities Staff. The two utility-regulation agencies had been the only parts of state government left unfunded when the fiscal year started July 1.

About 80 workers from the two agencies were sent home last week and told to return when the budgets are set. Commission chairman Lynn Posey said Friday that employees will be paid for the days they weren’t in the office, and they’ve been told to come to work Monday.

‘‘I’ve already called them,’’ Posey said Friday.

It was not immediately clear whether Republican Gov. Haley Barbour would accept the Public Service Commission budget. Barbour generally does not say whether he’ll sign bills until his staff has studied them.

Friday marked lawmakers’ second special session in two weeks. They met in a three-day budget blitz that ended at midnight June 30.

Mississippi legislators usually finish deciding how to spend money by early April, three months before the start of a fiscal year.

They delayed their deadlines this year to evaluate how the federal stimulus package would affect state government.

‘‘This has been the most difficult year in anyone’s memory for appropriations,’’ Lt. Gov. Phil Bryant said Friday as the Senate adjourned.

Legislators argued several months about the Public Service Commission’s request to hire additional staff members. The bipartisan compromise that passed the Democratic-led House and the Republican-led Senate on Friday allows the commission to redefine the duties of some vacant jobs. That way, the commission can hire people to help them evaluate legal and financial information from utility companies.

‘‘We’re satisfied,’’ Posey said.

Barbour opposed letting the commission expand its staff, but has made no public statements about letting the commission reshuffle some job duties.

The director of the Public Utilities Staff is appointed by the governor. The agency monitors utility companies’ finances and evaluates requests for rate changes, then sends its findings to the three elected members of the Public Service Commission.

Commissioners Posey and Brandon Presley, who are Democrats, and Leonard Bentz, who is a Republican, are relatively new to their jobs. They said they need employees to help them analyze information received from the Public Utilities Staff.

The PSC currently has only one attorney. Commissioners have said that in most other states, utility regulators have more than one person to offer legal guidance.

Rep. Preston Sullivan, D-Okolona, said the commissioners deserve to have the kind of staff they want.

‘‘They want to make a right and just decision. But they want to have the material in front of them, the right advice in front of them, to make that decision,’’ said Sullivan, who’s vice chairman of the House Appropriations Committee.

Only a governor can call a special session, and he controls the agenda.

The House voted Friday to give $8.2 million to community mental health centers — an issue that Barbour did not give lawmakers permission to consider. House Speaker Billy McCoy, D-Rienzi, ruled that the House could consider mental health funding because it is part of the overall budget.

The governor last week vetoed $7 million in spending for the 15 community mental health centers, which provide outpatient services. He said he did it because lawmakers had taken too much money out of the state’s financial reserves.

Health advocates have warned that people who are mentally ill could be put into county jails to await space in state treatment facilities.

‘‘That’s an abomination against God is what that is,’’ said House Public Health Committee Chairman Steve Holland, D-Plantersville.

Senators did not consider the mental health funding Friday because Bryant said doing so would have violated the state Constitution.

The bills are House Bills 1, 2 and 3.