Love blossoms in the sweltering heat of an unnamed South American country during a blood-spattered hostage crisis in director Paul Weitz’s slow-burning thriller.

Based on the novel by Ann Patchett, Bel Canto punctuates the stand-off between gun-toting rebels and an unflinching government with soaring arias performed by US soprano Renee Fleming, whose impeccable trills are lip-synced by Oscar winner Julianne Moore.

These operatic interludes strike a deep emotional chord but the melodrama enveloping them, adapted for the screen by Weitz and Anthony Weintraub, is frequently off-key and struggles to kidnap our undivided attention, especially in a pedestrian middle act that engineers carnal desire between guerrillas and their captives.

Moore catalyses polite screen chemistry with co-star Ken Watanabe that barely simmers and certainly never achieves boiling point, weakening a confidently staged and tragic finale fit for an opera, albeit in pyrotechnic-laden slow motion.

Underwritten subplots are unnecessary padding, including one rebel who harbours a secret ambition to sing opera and ends up hiding in a tree when culture-starved comrades poke fun at his vocal exertions.

In contrast, Weitz’s picture doesn’t get off the ground.

Japanese industrialist Katsumi Hosokawa (Watanabe) travels to a politically volatile South American nation with translator Gen (Ryo Kase) under the auspices of building a factory to revitalise the ailing economy.

Vice president Ruben Ochoa (Eddie Martinez) hopes to secure Hosokawa’s investment by hosting a soiree at his home attended by dignitaries including Russian businessman Fyodorov (Olek Krupa), French ambassador Simon Thibault (Christopher Lambert) and his wife Edith (Elsa Zylberstein).

Hosokawa is a huge opera fan, so the evening’s entertainment will be a private concert by American soprano Roxanne Coss (Moore) and her pianist Christopf (Thorbjorn Harr).

During the recital, heavily armed guerrilla rebels led by Benjamin (Tenoch Huerta) storm the party.

They demand the release of political prisoners in exchange for the lives of the party guests.

Bel Canto is composed in broad, artful strokes which undermine the efforts of Moore and Watanabe to convince us of their characters’ amour fou.

Supporting characters aren’t fleshed out beyond their nationality and political leanings.

As the meandering narrative loses momentum, any resolution is welcome.