About 25 people attending mass at St. Hugh's Roman Catholic Church in Greenbelt yesterday walked out during the service, amid a mixture of applause and taunts, to protest the formal installation of the Rev. John P. Stack as pastor.

The incident, accompanied by taunts of "good riddance" and "start your own church," stemmed from tensions in the suburban parish since Stack's arrival last July.

He was transferred to St. Hugh's from St. Andrew the Apostle in Silver Spring where he had instituted changes that angered many parishioners, who flooded the archdiocese with complaints.

Four months ago, leaders of the St. Hugh's Parish Council, upset with sweeping changes made by Stack at their parish, complained to Archbishop James A. Hickey. There was no response from the chancery, but Stack threatened to sue the council leaders for libel.

Parishioners walked out yesterday to protest what they called the bishops' insensitivity to their problems.

"I used to love coming to church, and I'm just so upset about this installation," said Malia Murray, one of those who walked out of the 11 a.m. service, which was attended by about 350 people. "I feel like our church is dying. It's falling apart. And it's going to get worse."

Stack supporters, however, outnumbered the protesters.

"It was sad to see it happen, and I do hope those people will be able to work with Father Stack in the future," said Marty Snyder. "But if they're not willing to, perhaps it's just as well that they don't participate."

Stack said yesterday that he did not want to comment publicly about the dissension at his church.

Auxiliary Bishop Thomas W. Lyons said he was aware that "not everything has been smooth -- for some folks, anyway." But he told the congregation that the Roman Catholic Church has had a history of controversy, and he urged parents to set an example for the children and reconcile differences.

One of Stack's first moves as pastor at St. Hugh's was to fire the Rev. Richard Maloney, a teacher at DeMatha High School who had lived in the parish for four years. Stack also caused controversy when, instead of sharing decisions with the Parish Council, he cited canon law to the effect that the body was only "consultative."

Opponents called Stack an abrasive and despotic leader. They blamed him for alienating parishioners and for causing longtime lay volunteers to resign.

"This installation ceremony, we feel, is just rubbing salt in our wounds," said Adele DiLiello, a parish member for 25 years, who wore a black arm band yesterday. "We've pleaded for help from the archdiocese, and here they are, installing him right in front of everybody."

But Stack's supporters said at a reception after the ceremony that the priest is an excellent counselor to the sick, a good role model for children and a man of integrity.

"This is not supposed to be a democracy," said Ida Mae Muller, a parishioner. "We go with what the priest says. He's our shepherd."

"I think the people who left didn't do disrespect to Father Stack, but they were disrespectful of their own religion," said Serge Triau, who said he has known Stack from the priest's time at St. Francis of Assisi in Rockville.

"I thought it was outrageous to have anything like that happen in a church," said Jane Kolb of St. Francis.

Special correspondent Laura J. LaFay contributed to this report.