Der Rosenkavalier's Octavian is a curious case. He is the eponymous hero of a four hour long opera, and certainly the centre of all the action. But whether the opera is really about him is hard to say. Strauss gave him plenty to do and sing, but burst as he might with boyish sincerity, it is the Marschallin, the woman he first loves, then leaves, who is the emotional backbone of the opera.

Opera Australia's current production of Der Rosenkavalier underlines this friendly tug-of-war, casting an excellent Octavian alongside an exquisite Marschallin and, for good measure, a Sophie so loveable that she too comes close to stealing first honours. In Catherine Carby, Cheryl Barker and Emma Pearson, Opera Australia has three of the country's loveliest female singers; flanked by Manfred Hemm's echt-Austrian Ochs and a fine supporting cast, they give performances whose splendour transports this Rosenkavalier beyond the bounds of a dull production, into the realm of the sublime.

Brian FitzGerald's twenty year old staging, rehearsed this season by Roger Press, is not exactly bad; it's just not particularly interesting. Its traditional approach does clear the way for the beauty of the piece to shine without complication, but that simplicity becomes superficiality, presenting the bare action of the opera while ignoring all its psychology. Depth of characterisation is left largely to each performer: Barker and Pearson succeed most fully here, with subtly wrought portrayals, while Hemm offers a purely buffo Ochs, and Carby's Octavian falls in the middle, ardent but a touch too broad to be true. All, however, are charismatic: a godsend in a staging which, with a lesser cast, could easily make four hours feel like eight.

Catherine Carby's trim, silvery voice and lively stage presence equip her well for Octavian: she sings with clarity, refinement and unflagging energy. Hers is not an opulent sound, but gleams stylishly through Strauss's orchestration, and revels in the romantic and farcical possibilities of the role. But if Carby provides the smiles of the evening, it is Cheryl Barker who supplies the tears. Her Marschallin is this show's heartbeat, her palpable fragility framed in a portrayal both dignified and devastatingly human. This is no aloof grande dame; Marie Therese is only thirty-two, and Barker accordingly plays her as a woman still on the cusp of middle age, in whom the spark of youth is locked in a visible struggle against time's steady march. Her achingly direct delivery is underpinned by a dark, shimmering timbre which does justice to Strauss's swooning vocal lines but gives short shrift to self-indulgence - not a Marschallin to luxuriate in, but a searingly beautiful one.

It's hard to imagine anyone abandoning such a Marschallin, but Emma Pearson's adorable Sophie makes a remarkably strong case for Octavian's change of heart, avoiding ingénue simpering in favour of a sweet but strong-willed - and funny - young heroine. Her pearly soprano combines heavenly high pianissimi with dusky lyricism, imbuing both the music and the character with a depth beyond girlish prattling. Manfred Hemm's Ochs is a suitably horrifying marriage prospect. His conventionally comic portrayal drains his lechery of menace - he's more irritating than vile - but this is in keeping with the show as a whole, and his bumbling antics are mostly enjoyable. He's a light-voiced Ochs, but has growling low notes where it matters, and his Viennese accent lends the show a dash of local colour. Warwick Fyfe's Faninal is another comical joy, his voice carrying an authoritative stridency which makes his blustering all the funnier.

A crowd of ensemble favourites acquit themselves well in the supporting cast: a parade of stock characters whose two dimensionality - like that of the production - does its best work as background to the superlative performances of the principal trio. Jacqueline Dark and Andrew Brunsdon are all conspiratorial eyebrows and melodramatic delivery as Valzacchi and Annina, Stephen Bennett a stentorian attorney and police officer, and Teresa La Rocca's duenna is nicely arch if too light-voiced. Most impressive is Henry Choo, who tackles the Italian Singer's punishing aria in rich, flamboyant style. The chorus performs well in its fleeting contributions, with many of its members making solo cameos during the Marschallin's levée.

It's heartbreaking to see Strauss's extravagant marvel of a score confined to the abysmal pit conditions of the Opera Theatre, with orchestra necessarily downsized to fit. Maestro Andrew Litton copes superbly with imprisonment, however, drawing a hearteningly full, romantic sound from the AOBO. Where clunky staging threatens to undo several key scenes - the Presentation of the Rose and the haunting of the Inn, for instance - Litton's leadership ensures musical values are more captivating, and handles both conversation and sublime set pieces with aplomb.

Der Rosenkavalier is arguably Strauss's most popular opera, but in this hemisphere it's evidently still not a guaranteed bestseller: a fact made brutally clear by the disappointing houses the show has so far enjoyed, and not helped by a seeming lack of marketing by the company. For any show, this would be a shame, but for this Rosenkavalier it's well nigh tragic. Staging issues aside, this is a superlatively sung and acted show, and its three female leads in particular deserve - both individually and as an ensemble - to fill the theatre. It may be long, it may be pricy, but Sydneysiders take note: when Barker, Carby and Pearson reach that Act III trio, they'll make every effort of attendance worth your while.