Although Hong Kong film production figures are reaching all-time lows, producer-director-writer Wong Jing seems as busy as ever. Kung Fu Mahjong, his second release this month, is more obviously geared to current trends than last week's Set Up, with Wong (who shares the directing credit with Billy Chung Siu-hung) displaying his usual skill at mixing and matching elements from past and current box office hits.

The title's 'kung fu' and 'mahjong' reflect the two inspirations at the heart of this lowbrow farce. It's a gambling comedy of the type that was popular more than a decade ago, when movies such as God of Gamblers (1989) helped maintain Wong's position as one of Hong Kong's top money-making producers.

It also marks the first re-teaming of Yuen Wah and Yuen Qiu since their scene-stealing turns opposite Stephen Chow Sing-chi in last winter's hit Kung Fu Hustle. Bereft of Chow and his originality, Kung Fu Mahjong serves as a raucous reminder of bygone celluloid glories.

The film's chief asset is its elevation of the two Yuens from sidekick status to centre stage. Although not a married couple, as in Kung Fu Hustle, they again display considerable chemistry as mismatched lovers. Sai (Yuen Wah) is a conman intent on turning waiter Ah Wong (Roger Kwok Chun-on) into the Mahjong Saint (the film's Chinese title). Fei (Yuen Qiu) is Ah Wong's boss, a loudmouthed restaurant owner who has secret kung fu and mahjong skills. Although Ah Wong has a prodigious memory, Fei is opposed to her innocent employee entering the sordid world of gambling.

From beginning to end, the kind-hearted harridan reels off a string of truisms that give the movie an unconvincing moralistic streak, even as it delights in the vices it so vociferously decries.

In one of the film's more delightful bits of nonsense, Sai and Fei discover that they were once teen sweethearts. The duo's romance comes with flashbacks played by young actors whose teen-idol looks bear no resemblance to the middle-aged couple.

Kwok displays a pleasant sense of mo lei tau (screwball) in a role that starts out like Stephen Chow's naive gambling ace in All for the Winner (1990) and, after Ah Wong is beaten by criminals, turns into Chow Yun-fat's Rainman-like idiot in God of Gamblers. The pop culture references don't stop here, because Ah Wong displays more than a passing resemblance to Kwok's career milestone as a simpleton in the television series Square Pegs (2003).

Guest star Jade Leung Cheng acquits herself admirably as a cool-headed gambling ace.

The last part of the movie gets bogged down in mahjong minutiae that will be lost on non-aficionados. The intricacies of the game restore Ah Wong's mental health, proving Fei's thesis that mahjong possesses brain-recuperative power. If only it extended to Hong Kong cinema as a whole.

Kung Fu Mahjong is screening now