A strike or some form of job action by the Prince George's County police appeared imminent last night after contract negotiations between the county and police union representatives broke down.

Both sides rejected what appeared to be final contract offers at a negotiating session between County Executive Winfield M. Kelly Jr. and county Fraternal Order of Police President. Laney Hester at 7:30 p.m., just as the police union was meeting to decide whether it should strike or take job action.

Minutes before the police union meeting began, many officers expressed stron sentiments in favor of a strike.

The county and police association leaders offered different accounts of the offers that were presented at the meetings between Kelly and Hester. Kelly said that the county's final offer would have allowed police to retire after 20 years of service at 46 percent of top salary. Hester, however, said the county "did not really make that offer. If they did, we would have accepted it."

Hester contended that Kelly and Police Chief John W. Rhoads, in return for the early retirment package, decided to sharply cut the salary increments given to new policemen in the county's earlier offers.

"We're somewhat at a loss as to why they rejected it (the county's final offer)," said a Kelly spokesman. "This is the end of the rope. We've offered the most we can within the confines of being fiscally responsible."

Kelly said he felt the negotiations may have broken down because of what he called a communications problem. "Maybe the tensions of the last couple of days have had a bearing on it," said Kelly. "We hope things will settle down in a few days."

The strike talk has been fueled during the past week by Rhoads' firing of officer Peter L. Morgan for fatally shooting a fleeing shoplifter suspect last Christmas Eve, and the shooting deaths Monday of officers Albert M. Claggett IV and James Brian Swart.

The county police contract expired one year ago Saturday, and negotiations broke down Wednesday over the issue of retirement benefits.

The police seek the right to retire on full pension after 20 years on the force. The county would like to retain the current provision that requires an officer to put in 25 years before he can retire with full pension benefits, which amount to 50 percent of an officer's final salary.

County negotiators said that police demands for earlier retirement benefits would force the county to raise taxes in the near future. The police said the cost to the county would not be that great.

A similar stalemate occurred during contract negotiations in 1975, and police reaction was a six-day work slowdown.

On Oct. 14 of that year, officers began turning in their cars en masse, saying they needed repairs. State police and members of the sheriff's department filled in until the county obtained a court injunction ordering the police back to work.

Rhoads put the state police and various city police units on notice Wednesday, telling them their assistance might be needed by the weekend. The sheriff's department is half as large now as it was three years ago and officials said it could not afford to detail men to the county force.

"I'm still hoping cooler heads prevail on Thursday night," Rhoads said, after meeting with County Executive Winfield M. Kelly Jr. on Wednesday. "I think the men know what they would be doing by striking , the type of consequences a strike could have. It would destroy all the work we've done building relations with the community the past few years."

But Laney Hester, president of the Fraterna Order of Police, was adamant yesterday afternoon, insisting that anything that happened would be the county's fault.

"Winfield Kelly, Don Weinberg (the county negiotiator) and the rest of them could solve this thing in five minutes." he said. "Our demands aren't unreasonable and they know it." A panel of federal fact-finders supported the police department's retirement demands, police officers pointed out.

"We don't want to do anything that will hurt the people of this community; that's not for us. But we haven't been able to get what we want for a year now, so we have to apply some pressure. Pressure is what negotiating is all about."

Hester said yesterday that he believed 95 to 98 percent of the men on the force (from lieutenant on down) would support a strike.

As members of the force dispersed after the funerals of Claggett and Swart yesterday, there was considerable discussion about last night's meeting.

"What's going to happen" one officer said. "You'll know at 7:31 (one minute after the meeting was scheduled to begin). I don't think it's going to take us very long to let Laney know what we want to do."