Prince George's County Executive Lawrence J. Hogan, in his fourth day on the job, yesterday announced a series of cost-cutting measures that he said he will implement immediately in an effort to "make government more accountable to the citizens."

The measures were greeted with varying degrees of confusion and skepticism by several county officials, however, who said that many of Hogan's economy proposals are either already in practice or unworkable.

Hogan said that he will review all county hiring and overtime requests personally, prohibit employes other than police from taking home county cars and return four cars assisgned to the executive's office to the police department in his first efforts to cut government costs.

In addition, Hogan said that all county printing expenditures will have to be approved by one of his staff and that he has ordered that the police department stop "taking five officers off the street to work for the executive's office."

The new county executive, who was elected with a mandate to trim the budget, also said he is working on a plan to extend the hours of the county switchboard in Upper Marlboro from the present 8 a.m. to 4:30 p.m. schedule to one from 7 a.m. to 7 p.m. He said this expanded system would allow operators to channel questions and complaints to the proper county officials.

"The bottom line," said Hogan, "is that we're trying to cut expenses."

The bottom line for the persons and agencies affected by these measures was not so clear yesterday. Police officials disputed Hogan's accounting of officers and cars. Budget and personnel workers wondered openly about the executive's ability to examine all overtime payments personally. And of the expanded switchboard center, one operator said: "I'll go along with what he wants -- I have to -- but I don't think it makes any sense."

Robert Duncan, the county's budget director, said he did not think it would be difficult for Hogan to review and approve all hiring personally. "We can save up batches of them," said Duncan, "and go to him every two or three days."

But overtime, Duncan said, is a different matter.

"It's not always the black-and-white decision it might appear to be," Duncan said. "And I don't think he really wants to sit down and review 500 slips of paper every week." About $120,000 every two weeks, or 4 percent of the county's payroll, is overtime pay, Duncan said.

"I think that the best way to interpret this," Duncan said, "is that Hogan wants to get a handle on just what's happening, and give his department heads some direction of what he wants for overtime."

Asked about overtime paid for emergency situations, Hogan said, "We'll have to check on that. We will have to meet with the department heads and set up some strict parameters under which [emergency overtime] can happen."

"If it turns out that police are incurring this emergency overtime because of their four-day week," Hogan said, "we might have to go to a fiveday week for them."

County Administrator Robert Wilson was puzzled by Hogan's order that county employes not be allowed to take county cars home, except in emergencies. Since 1976, Wilson said, only the fire chief and several fire battalion commanders have been allotted county cars, in addition to police officers.

Hogan said that his announced policy on county cars did not differ from the present one, but added, "It's not working that way." He charged that many county cars were being taken home by county employes at night, despite the rules.

Police disputed an announcement made yesterday morning by Hogan aide Lewis Helm that five cars have been returned to the department from the executive's office.

A police spokesman said that only three of the department cars had been given to the executive, and two have been returned.

Hogan said he believed that all these cars "had come out of the police budget," but he lowered the number returned from five to four.

"Actually, we kept Kelly's car," Hogan said. "The police wanted it back, they said they had a buyer for it, but we kept it because we thought the buyer was a friend of... someone. We'll keep it around."