Brenda Blethyn might seem a strange choice to play Archie Rice, but a female version of Laurence Olivier’s end-of-the-road performer from John Osborne’s play and Tony Richardson’s 1960 film is essentially what Jean Dwight, the character she essays in this Australian dramedy, amounts to. Meanwhile Jean’s son Tim, played by Khan Chittenden, is a still-virginal young man looking desperately for sexual release, but still living under his mother’s thumb. So what one gets in “Introducing the Dwights” is a weird amalgam of “The Entertainer, Distaff Version” and “American Pie Down Under.” And as if that combination weren’t enough, the family is also provided with another son, one who’s brain-damaged and spastic, yet intelligent and charming. It’s no wonder the movie proves even more dysfunctional than the Dwights themselves.

Jean is a woman on the wrong side of fifty who was an up-and-coming music hall performer years ago in her native England but saw her career end when she moved to Australia with her husband, a singer who proved a one-hit wonder, and left the business to raise their two sons. Now, separated from John Dwight (Frankie J. Holden), a security guard at a local grocery, she’s trying to resurrect her act as The Raunchy Housewife, a brassy comedienne, while holding down her day job in a cafeteria. To care for her disabled son Mark (Richard Wilson)—and to cart her about to her low-rent gigs—she depends on Tim, a dutiful fellow who also uses his truck to run a moving business.

It’s while moving roommates Kelly (Katie Wall) and Jill (Emma Booth) that he catches the latter’s eye. Unfortunately his profound shyness—the result, it would appear, of his mother’s control-freak mentality, as well as her habit of interrupting any time they might try to spend together and of treating Jill with contempt when Tim introduces her-imperils any chance their relationship might have. Add to that Mark’s periodic wise-beyond-his-disability interventions and Mama Rose’s—sorry, Jean’s—preparations for both a big benefit appearance and an important audition, not to mention the death of a neighbor with whom Jean was apparently once close, and you have a recipe for a picture crowded—overstuffed might be a better word—with incident. Needless to say, there’s a feel-good finale that seems totally unearned.

Among the actors, Chittenden comes off best; his initial nervousness with Jill is overdone, but that’s probably the fault of Cherie Nowlan’s sledgehammer direction, which italicizes almost everything, and for the most part he does a nicely laid-back, likable turn. So does Holden as the surprisingly good-natured father, while Booth makes Jill appropriately torn between horror at Jean’s behavior and affection for Tim. Wilson’s probably as good as could be hoped as Mark; the character, which careens between neediness and precocity, is just too synthetic a creation for anyone to make credible.

Then there’s Blethyn, who works as hard as Jean as the character does when she tries to sell her dreadful stand-up routine. Eventually the stridency becomes exhausting, and you wind up wishing someone would use the hook and yank her offstage. Technically the movie passes muster, but no more; Mark Wareham’s lensing is erratic, going especially awry in the tenser dramatic moments, and Scott Gray’s editing lets things ramble on to nearly two hours.

The original Australian name of the picture, incidentally, was “Clubhouse,” and it screened under that moniker at this year’s Sundance Festival. Despite the title under which Warner Independent Pictures is releasing it in this country, you’d be well advised not to make this family’s acquaintance.