LEWISTON – As Maine’s Catholic church prepares its parishes for fewer priests, several Lewiston-Auburn churches will see a new priest.

Beginning June 1, the Rev. James Morrison will take over as temporary administrator for Holy Family Parish in Lewiston, while its priest, the Rev. Claude Gendreau, is away on medical leave.

Then, on Sept. 1, Morrison will move to a permanent role in Auburn, where he will serve as an assistant administrator to the city’s three Catholic parishes and churches in Mechanic Falls and Norway.

It’s all part of a shake-up that’s scheduled to continue until at least 2010, said Sue Bernard, spokeswoman for Maine’s Catholic churches.

The problem is that Maine’s priests are aging. More are retiring than are entering the diocese. By 2010, the number of active diocesan priests is forecast to fall by 20, from the 85 now to 65.

“We’ve seen this coming, Bernard said. “When you lose even one, the dominoes start falling.”

On Monday, her office issued details of new priest assignments to dozens of southern and central Maine churches. They also listed the retirement of priests in Falmouth, Limerick and Kittery.

Two more waves of assignments are expected to be announced in the coming weeks, Bernard said.

“We’re trying to get these people in place as the vacancies occur,” Bernard said.

Rev. Morrison, who has served as the pastor at St. Maximilian Kolbe in Scarborough for six years, was moved to make room for the consolidation of pastors at his church and St. Bartholomew in Cape Elizabeth.

In Auburn, he’ll replace the Rev. Kevin Martin, who plans to begin studies in the fall at the Pontifical University of St. Thomas Aquinas in Rome. Martin, who was ordained in 2003, plans to complete a master’s degree in moral theology.

Martin serves all three of Auburn’s Catholic parishes – Sacred Heart, St. Louis and St. Philip – and Our Lady of Ransom in Mechanic Falls and St. Catherine in Norway.

There’s no telling how long any priest will stay at his new assignment, Bernard said. Until recently, most assignments lasted either six or nine years.

“Catholic parishioners are used to some changes,” Bernard said. “This time, I can’t say that there is a pattern. We’re doing the best we can.”