An enormous rococo sofa dominates the stage. Great artworks jostle for space on the walls – Picasso, Velázquez, a handful of impressionists, and a banner reads “Happy birthday boss”. Guests pour in from a pinging elevator: a maelstrom of big skirts in Disney princess colours, high-rise hair, three-piece suits and pork pie hats. Out of the window: skyscrapers.

In singer turned director John Savournin’s latest production for Opera Holland Park – a collaboration with Scottish Opera and D’Oyly Carte Opera – Franz Lehár’s hit operetta The Merry Widow switches fictional Pontevedro and Le Gai Paris for New York’s mafia underworld and its Sicilian homeland. The plot’s patriarch becomes a pinstripe Manhattan godfather, title character Hanna Glawari the widow of a Sicilian lemon-tree racketeer.

In their energetic English version, Savournin and David Eaton have fun with Dolmio-level Italian (no less authentic than Lehár’s original Balkan Neverland) and these mafiosi reach as often for the TV gangster phrase book – “Bada bing, bada boom”, “schmuck”, “capeesh?” – as for their guns. Dialogue is delivered in 90% faux mafioso (“family comes foist, bowss!”), 10% operatic RP. In the mostly excellent singing those proportions were reversed. And where the spoken passages were largely shrieked or shouted, the balance in the sung numbers swung in favour of the orchestra: most of the action played behind the pit thus vastly increasing the demands on singers already working in tent-acoustics.

So much high-camp melodrama may leave some yearning for a calmer take on Lehár’s classic. But, for those with a higher tolerance for hyperactive kitsch and national stereotyping after Lehár’s own model, this mid-century Merry Widow is enormously enjoyable. Come for the big tunes, stay for the straight-legged “Russian” folk dance performed unsmiling in dark glasses, the stage hands in white tie, lemon trees on wheels and the “birthday cement mixer” (don’t ask). For Acts 2 and 3, takis’s streamlined set spins to take us from a cypress-equipped villa to the crimson interior of Maxim’s – now a “respectable performance bar” in New York.

Bass-baritone Henry Waddington is ideally cast as “Don” Zeta and evidently had a ball, his comic timing impeccable; Rhian Lois was a vivacious stage presence as his wife, Valentina. Matthew Kellett’s Little Italy accent was the best of the bunch, while Christopher Nairne and Connor James Smith made one winning double act as warring Italians, Amy J Payne and Matthew Siveter as another, the ferocious “Russian” Kromows. But this is also a piece with a big heart. Along with the warm, stylish playing from the orchestra of Scottish Opera under Stuart Stratford, it was the suavity and occasional tenderness of Alex Otterburn’s Danilo and Paula Sides’s Hanna that made this performance more than the sum of its gags.

• At Opera Holland Park, London, until 28 June.