After two concerts in Melbourne and two in Adelaide, the Mormon Tabernacle Choir has gained at least a toehold on Australia, the accommodating continent Down Under.

There appears to be a deep rapport between Aussies and Yankees, and one feels instantly at home in this vibrant and optimistic society.The choir initiated its Australian sojourn with two concerts June 25 in Melbourne's Concert Hall, part of an elaborate arts complex that makes Lincoln Center or Kennedy Center look a little threadbare and bare-bones by comparison.

The hall seats 2,677 on a main floor and two balconies. Its clear, yet mellow sound can be adjusted with acoustic banners and Perspex shells to create different acoustic responses. Walls are painted in subtly blending waves of coral, sand, lavender and gray, with aisles carpeted in a luscious soft shade of red-orange.

Attendance was big in Melbourne, with a full house in the evening and nearly as many in the afternoon. Programming, however, seemed a little heavy for the Australian evening program with Mendelssohn's long and not especially interesting "Hymn of Praise" with its many solos taking up a great deal of the time. Indeed, the audience was left hungering for the "real" Tabernacle Choir until the last half-hour of the program. In Adelaide some judicious cuts in the Mendelssohn left a maneuverable program that offered more of the sort of music the public has long associated with the choir through its records and broadcasts.

The audience responded enthusiastically, and one feels that the Australian tour is now off to the sort of countrywide triumph that will justify the vast expenditure of energy, the high expectations aroused and the advance sellouts.

Advance publicity has been coordinated by a remarkable young man, Michael Otterson, public affairs director for The Church of Jesus Christ of Latter-day Saints for the South Pacific. Radio and television advances, newspaper stories and any number of personal contacts are giving the choir higher visibility than in any tour one can recall.

The choir's final appearance in New Zealand was in Christchurch's beautiful Town Hall, a building of similar elegance to Wellington's Fowler Center. The concert was a triumph, with glowing critical acclaim. The choir's more subtle numbers, such as Randall Thompson's "Fros-tiana," show to better effect in a place of such clear acoustics.

Philip Norman of the Christchurch Press noted the choir's "soft-edged, gauze-coated tone" in show tunes, and its deserved reputation, its "professional ease and impeccable polish." He even observed that it might not be too bad to come back in his next life as a Mormon.

Physically there have been smoother tours. Sickness has felled many. As many as 30 singers have been off stage at a time with flu and colds, mainly due to strange viruses and the sudden change of season, though the weather has been generally fine. Most alarmingly, conductor Jerold Ottley was run down by a scurrying stagehand backstage in Melbourne and his head knocked against the wall. Concussion was feared, but he rallied and has had no lasting ill effects worse than a sore head.

Nonetheless, choir members have enjoyed the sights of Melbourne and Adelaide with their customary zest, including a trip through the rolling green countryside to the Healsville Sanctuary to consort at close range with kangaroos, wallabies, koalas and many exotic birds.

Tuesday morning the entourage flew west to Perth, a metropolis of one million residents on the Indian Ocean. Two concerts are scheduled there Wednesday, before the choir flies to Sydney on Thursday.