The China Incident, written, directed and designed by Peter Houghton. Lighting design by Michael Jewell, sound design by David Franzke. With Anne Browning. Newtown Honey by Marty Dennis, directed by Beng Oh. Lighting design by Matthew Barber. With Lauren Clair and Curtis Fernandez. La Mama Theatre until July 15.

These two shows demonstrate one reason why La Mama is so important. If diversity is crucial to a species' survival, then us addicts of the thespian art owe La Mama a big bunch of flowers for making sure that the Melbourne meme pool is full of creatures wondrous, various and strange. Its current season is a case in point: it's hard to imagine a greater contrast than between these two pieces. Intriguingly, they both feature theatrical couples; but there the resemblances end.

The China Incident is a comic monologue, a companion piece to Peter Houghton's one-man hit The Pitch, this time with Houghton in the directorial seat and his wife Anne Browning, who directed The Pitch, as the performer. Newtown Honey features the married actors Lauren Clair and Curtis Fernandez and is a two-hander, a powerful piece of poetic theatre that is like a cross - if you can imagine such a beast - between Franz Xaver Kroetz and Dylan Thomas.

On one level, The China Incident is, like The Importance of Being Earnest, a convoluted excuse for a bad pun. In its relentless satire of the media-driven hyperreality that shapes so much of contemporary life, it is quite clearly related to The Pitch, and it shows off Houghton's gift for writing lines that biteth like the serpent who's had a bad run-in with Steve Irwin.

Anne Browning plays Bea Pontifec, a high-powered diplomatic consultant, who is a kind of Ann Coulter with power (one would like to call it a fiction, if it weren't for Condi Rice). It begins with a fine moment of theatrical instability: Browning enters the space seemingly talking to herself, until you realise that she is on the hands-free mobile. As she takes off her overcoat, revealing the obligatory pinstripes, she turns toward a desk covered with five different coloured phones - the red one is the direct line to the President of the United States - the aforementioned mobile and a laptop. And behind her is an intercom.

And it's a hundred miles an hour from there. The phones ring constantly, and Bea juggles calls from an African dictator who wants his massacres massaged for the world community, the President (who wants to know about her underwear), her lover at the UN and her PA. She has reached a peak point in her career - she is to be the circuit breaker in the deadlocked five nation talks involving North Korea and China. Unfortunately, as her career rockets into hyperdrive, so does her family life. Her daughter is getting married, her son has just been busted for drugs, she's fighting with her daughter, the gay male bridesmaid, her future in-laws and her ex-husband, and those phones just keep ringing...

Of course you see the punchline coming, but it's no less funny for that. The play gives Houghton an excuse to let fly at a range of contemporary targets, from neo-con media spin to PC family relations. Bea is a monster, but she's monstrously familiar. And you can't but admire the split-second ferocity of Browning's frenetic performance and David Franzke's sound design. It's not as straight-out hilarious as The Pitch, which permitted Houghton the freedom of slipping in and out of a dizzying variety of roles, but it's a marvellous conceit which makes an intelligently diverting hour in the theatre.

Marty Denniss' Newtown Honey is a complete change of pace. Denniss's first play, it premiered in Sydney a decade ago with the same lead actress, which perhaps explains something about the commitment and depth of the performances. It's a passionate, surprising work, given a sparely imaginative production by Beng Oh, which demands (and rewards) close attention.

Maddy (Lauren Clair) and Loos (Curtis Fernandez) are lovers, caught in a relationship of almost claustrophobic intimacy in which they have insulated themselves against a world they do not understand, and which does not understand them. From the moment Loos appears, frightened and panting, on stage, we know that something is wrong; and the play follows their attempts to remember their pasts in order to remake the present, as they weave together their mutual stories in an attempt to find a truth that you sense is already lost to them.

Despite obvious differences, this play reminds me irresistibly of Kroetz's bleakly beautiful two-hander Michi's Blood, about another outsider couple withdrawn from the world, their future symbolised by a pregnancy. Both plays contemplate the nature of love in ways that would not be recognised by Hallmark; and, as has been said of Kroetz's work, Denniss's play gives you the sense that you are witnessing "a crack-up at the edge of truth".

Where Denniss differs markedly from Kroetz is in the richness of his language; where Kroetz's doomed lovers speak a blasted, impoverished vernacular that leaves his characters lost in the gaps between their experience and what is expressible, Maddy and Loos have invented a private language that articulates their despair and love with a tough, ragged beauty. At moment it segues into moments of pure poetry (and sometimes even verse - Denniss is not afraid of rhyming); but this is a poetry of the theatre, meant to be enacted through bodies, and it is never mere lyrical decoration.

Beng Oh - whose direction I've encountered once before, in the bizarre but effective Shakespearean play The Nero Conspiracy - gives this play an intelligently simple production that permits its theatricality full flower. All the action takes place on a thin strip of carpet at the far end of the tiny La Mama stage, creating a necessary alienating space between the performers and the actors. The action is abstracted - when Loos lights candles, for example, Fernandez simply draws them on the wall - which focuses the attention where it ought to be, on the script and the performers.

At times the density of the language left me uncertain what was happening, and I think it would take a second viewing to be clear about the details. But for me, that didn't matter; I was riveted by the intensity and truthfulness of this production, and the complexities that were woven and unwoven before my eyes. Clair and Fernandez give extraordinarily generous and sure performances, creating the discomfort that comes of witnessing the unspeakably intimate moments between human beings. Newtown Honey seems to me to be theatre of an unusual integrity: not perfect, perhaps, but most certainly exactly what it is, which is not nearly as common as it sounds.