Dame Kiri Te Kanawa might be New Zealand's national treasure, but across the Tasman her star is just as bright - bright enough, at any rate, to draw an enthusiastic crowd of Sydneysiders to the Opera House for a concert of operatic favourites. Backed by the Sydney Symphony, under Brian Castles-Onion's exuberant leadership, Te Kanawa offered a generous selection of arias interspersed with some suitably showy opera overtures.

The concert opened with a set of Mozart arias, a fitting beginning given how crucial this composer has been to Te Kanawa's career. Pamina's "Ach, ich fühl's" and the Countess Almaviva's were an affirmation of Dame Kiri's place among the finest Mozart interpreters of our time, sung with refined lyricism and silky legato line. Characterisation may have been a little on the generalised side, but when that default persona is so thoroughly disarming, it's difficult to fault.

A suitably raucous account of the Bacchanale from Saint-Saëns' Samson et Dalila followed: an orchestral frenzy which drew the first cheers of the night, many of them no doubt for timpanist Mark Robinson's virtuosic contribution.

The Mozartian mood now broken, Te Kanawa returned with a bit of warmer repertoire, in the form two Argentinian songs. Of these, Guastavino's soft, swaying "La rosa y el sauce" was probably better suited to the soprano's talents; her vampish take on Ginastera's "Canción al árbol del olvido" wasn't quite so convincing. Both songs suffered, however, from overly hushed delivery - as did the final selection of the first half, the final scene from Strauss's Arabella, where her miniaturised approach too often slipped from admirable intimacy into outright inaudibility. Her artistry, however, was impeccable as ever, and her voice, when it opened up, was resplendent.

Audibility would remain an issue throughout the concert: whether as a result of caution (arguably unnecessary) or of the concert hall's problematic acoustic was difficult to tell - it may well have been a combination of both. Either way, it was unfortunate; apart from a slightly acidic edge to the middle register, Te Kanawa's voice remains in remarkably good shape, and it was a shame not to hear it to better advantage. That said, there is a certain brand of prima donna poise which tends to conquer all, and it's a quality Dame Kiri possesses in abundance: her charisma and sensitive artistry turned what could have been a deal breaker into a surmountable frustration which, in any case, was probably lost on the more adoring devotees in the audience.

The second half of the concert took a similar form to the first. The swirling overture to Verdi's La forza del destino brought us into the world of Italian opera, and Te Kanawa remained there with a bracket of Puccini arias. Liu's "Signore, ascolta" and Mimi's "Donde lieta usci" continued the plaintive theme which had characterised much of the first half, but for all of their sighing pianissimi, it was in the jollier "O fior del giorno", from the little-known Edgar, that Te Kanawa was at her best and brightest.

After a riotous trip through Bernstein's Candide overture, she returned to deliver one of the highlights of the evening: Marietta's Lied from Korngold's Die tote Stadt, a piece of wistful Viennese gorgeousness which fits Te Kanawa like a glove. The final programmed aria was likewise lovely: the whispered rapture of "Depuis le jour", from Gustave Charpentier's Louise was nicely realised, with the quietness of Te Kanawa's delivery now a positive asset.

There were encores, of course. An already excitable crowd broke into pop concert cheers at the opening phrases of "O mio babbino caro", the operatic hit which Te Kanawa herself popularised via the film of A Room with a View. In context, the aria is a teenage tantrum; in concert, it can be made far more poignant, and Te Kanawa's rendition tugged heartstrings in all the right directions. She did so while very sweetly turning full circle, acknowledging all those who had booked seats in the choir stalls behind her. Most striking of all, however, was her unaccompanied rendition of the traditional Maori song "Pokarekare Ana" - a touching tribute to her homeland, and a perfect conclusion to what was, despite its flaws, an enchanting evening.