The 150-year-old granite building which requires extensive refurbishment was originally built to house 80 members of the religious order but diminishing numbers and the ill-health of some elderly priests mean it is no longer deemed a suitable residence.

Mount Argus church, a protected structure built 20 years later, adjoins the monastery and because of curtilage, the facade of the older building will have to be retained by any new owners.

"The building will be sold under the condition that any future use will be compatible with the fact that it's attached to the church, " says congregation Superior, Father Frank Keevins. "We did think initially that the building might be suitable for use by another religious order or by a health institution, for example. The problem is that any renovation is going to be a major undertaking."

Father Keevins believes the building could also be converted into offices or used for some other commercial purpose. "In reality though, we'll probably have more say in what it won't be used for than what it will.

"There are three basic reasons behind the move, "he says. "It's too big, it's too costly to run and it's unsuitable for the 14 or so elderly men who currently live there.

"Our intention is to build a smaller, purpose-built monastery on what is at the moment our garden area."

The order is also considering what they call a "front field" on Kimmage Road, a parcel of land which could be as sizeable as seven acres.

According to estate agents, at current prices this would fetch 5m-plus per acre. "At the moment our focus is on selling the old monastery to fund a new one." The Passionists congregation was founded in the middle of the 18th century.

There are currently about 60 members of the order living in this country.