Prince George's County Executive Winfield M. Kelly Jr. unveiled his long awaited plan yesterday to create a separate new corrections department that would take over operation of the county jail and the transportion of prisoners from the County Sheriff Department.

Kelly said the reorganization plan, which will require County Council approval, would save the county money and be more efficient than the existing system. The new department would be headed by a $40,000-a-year director, as yet unchosen and subject to County Council confirmation.

The new department would be carvd from the present sheriff's office. A slimmed-down headed by the $25,500-a-year elected sheriff, would have responsibility for court security and the service of civil papers.

Kelly had advocated a similar reorganization plan two years ago, but it proved to be politically unpopular. This week, Kelly met with judges, politicians, Sheriff Don E. Ansell and, separately, Ansell's deputies, before announcing his decision.

"What a mess," declared Jim Hubpard, president of the Deputy Sheriffs' Association, the foremost opponent of the reorganization. "The 270 men of the department are being moved around like pieces of furniture."

The reorganization proposal comes at a time when Ansell and members of his department are under investigation by the State's Attorney's Office for alleged irregularities. Ansell has said he would like to head the new department, but the investigation's outcome could affect Answell's chances.

"Ansell will be given careful consideration," said Kelly aide John Lally, who volunteered also that the $40,000 slot will be nationally advertised "We're not going to comment on any investigation underway, but we're not going to assume anything about guilt or innocence until there is a proper legal determination.'

Lally said that Kelly had made "no commitments to anybody" for the job.

Ansell said that whether he accepts the post if offered "depends on what they're going to do with it (and) the amount of authority" vested in the corrections chief. He declined comment on the criminal investigation, which is weeks away from completion, according to State's Attorney Arthur A. Marshall Jr.

As outlines by Kelly, the reorganization plan is not unique to Maryland or to the country. It is patterned after what county planners regard as a "national model" in Jackson County, Mo.

Kelly called for the new department to begin independent operation Jan. 1 with 147 positions now in the sheriff's office.

"All correctional positions in the new department will be publicy advertised," according to a summary of the plan. "First preference for selection will be given to qualified applicants from the sheriff's department . . ."

The decision to transfer responsibility for the transport of prisoners to the new department will require state legislation, the summany said. An other element - shifting criminal warrant service from the sheriff to the county police - will require agreement from the county's Circuit and District Court judges.

The criminal warrant shift would involve the transfer of 37 slots to the county polie from the sheriff's office, the staff of which would be reduced from 278 employees to 65.

Kelly also proposed, as part of the package, the creation of a corrections department citizen advisory department that would be appointed by him subject to approval by the County Council.