It’s been 12 years since James Cameron became king of the world with the Oscar-winning Titanic. The tragic love story between Kate Winslet’s socialite and Leonardo DiCaprio’s scallywag aboard the doomed ocean liner shattered box office records and countless hearts to the warbling of Celine Dion.

The script may have been flimsy but as a thrilling spectacle, Titanic was hard to fault. Since then, Cameron has explored the limitations of IMAX technology in the underwater documentaries Ghosts of the Abyss and Aliens of the Deep, all in preparation for the special effects extravaganza Avatar, said to be the most expensive film ever made.

Every nickel and cent is up there on the big screen as the writer-director melds live action with state-of-the-art digital effects to evoke a 21st-century world on the brink of extinction.

Paraplegic war veteran Jake Sully (Sam Worthington) signs up for a tour of duty on the planet of Pandora, which is home to the peace-loving Na’vi. This magical world, which cannot support human life, conceals vast deposits of an ore, which sells for $20m per kilo, and Parker Selfridge (Giovanni Ribisi) plans to mine the rock for vast profit.

Unfortunately, the richest seam lies directly beneath a gargantuan tree, which is home to the Omaticaya tribe led by Eytukan (Wes Studi) and his wife Mo’at (CCH Pounder). Selfridge intends to send in bulldozers in three months time, using warmonger Quaritch (Stephen Lang) and his troops to clear the area. So Jake agrees to work alongside pioneering scientist Grace Augustine (Sigourney Weaver), who has developed a method of fusing the minds of human ‘drivers’ with Na’vi avatars, which can move through the forest and gain the trust of the indigenous people.

As his Na’vi alter ego, Jake falls in love with Eytukan and Mo’at’s daughter Neytiri (Zoe Saldana), who has been promised to warrior Tsu’tey (Laz Alonso). Together they must somehow defeat Quaritch and his heavily armed gunships.

Avatar is a dazzling spectacle that creates a fantastical kingdom. Awesome technical might bludgeons a sophisticated narrative or subtle characterisation.

Worthington’s hero has a simple narrative arc from spy to defender of the Na’vi realm, standing before the tribes to deliver a climactic rallying cry.

Villains of the piece are crudely sketched, from Lang’s hilariously muscled brute to Ribisi’s corporate weasel, who dismisses the Na’vi as “blue monkeys”.

Underlying messages about the relentless pillaging of Earth’s natural resources are hammered home with Cameron’s typical bluntness, and there are chilling echoes of September 11 in a centrepiece sequence.

The film screens in 3D and IMAX 3D in selected cinemas and the technology is employed to impressive effect.

Cameron promised us a visually stunning adventure like nothing we have seen before. He delivers.