Once they had all crammed themselves into the Prince George's County Administration Building -- the campaign workders, the county employes, the job seekers of every persuasion -- Lawrence J. Hogan had one simple message for them.

"I'm going to cut the budget," the new county executive repeated again and again yesterday. "That's my only promise."

It was the same promise that had carried Hogan, a Republican, from political retirement to a resounding victory over incumbent Executive Winfield M. Kelly Jr. and the county's powerful Democratic organization.

And, in a county which has made government austerity its new political gospel, Hogan's message was one which provoked loud cheers from the hundreds who packed the County Council chambers to see the new executive and 11 council members sworn in.

"It will not be easy," Hogan said, "we have an avalanche of problems facing us, major and minor." He called it "the most important and difficult job I have had... the greatest challenge of my career."

Hogan said that the one problem facing the county which "cried out for comment" is race relations. "Let us demonstrate," he said, "that the handful of racists among us are not typical.... "The Ku Klux Klan and "black racists" as well as "other purveyors of hate," Hogan said, are "unwelcome."

An early priority, Hogan added, will be addressing "the financial duplications in our hospitals and health care systems," and he said he would immediately appoint a task force to "scrutinize" health care services in the county.

Hogan's first challenge will be cooperating with the all-Democratic council, which yesterday spoke optimistically but somewhat cautiously about the county's new partisan government that marks the end of four years of complete Democratic control of county government.

"It remains to be seen [whether Hogan can cut the budget]," said Council member William B. Amonett, who yesterday announced that he would have unanimous support from council members today in the election for council chairman. "New voices say new things. All the things [Hogan has said about cutting the bud&et] are -eanuts."

"Hogan is going to push and push and push until we push him back," said council member Gerard T. McDonough, who has already emerged as one of the council's new leaders. "Then he'll back off, and start pushing somewhere else. Eventually, we will reach a balance with him."

Council leaders have already pushed back twice. Last week a delegation of county Democratic leaders met with Hogan to complain about the abrupt firing of county detention center director Dr. Weldon McPhail, the county's only black department head. Hogan reportedly insisted on having "my own man" at the detention center, but agreed to offer McPhail another county job.

A second dispute is brewing this week over Hogan's apparent decision two weeks ago to offer Joseph M. Parker the position of county personnel director. Council members told Hogan that they would oppose the appointment and sources said yesterday that Hogan was now backing off from the move, to Parker's dismay.

"I want the job and I feel I'm qualified for it," said Parker, who offended many county Democrats during his aggressive campaign against 25th District state Sen. Tommy Broadwater Jr., the party organization's black leader. "I hope to meet with Mr. Hogan to discuss it again."

Former County Executive William Gullett, the county's last Republican executive, cane out for the ceremonies yesterday and chuckled when asked Hogan's future with the council. "He should have it easier than I did," he said as he watched the crowd at Hogan's inauguration reception in the county executive's office suite. "The council is more mature now -- there was a whole motion of opposition to me."

Gullett was Just one of the dozens of present and former county dignitaries, officials, and would-be officials who crowded into the executive's suite and waited in line to shake Hogan's hand. Most had a well-released greeting or request for him.

"This is the first time I've felt welcome here," said Fraternal Order of Police President Laney Hester as he filed by.

"You are welcome," Hogan would say as one person or another wished him well. "I appreciate your support. I'm going to be coming to you for help." And, between sips of champagne and grabs for hands, the ubiquitious refrain: "Cut the budget. Don't worry, I will."