Somewhere in the psychedelic haze of pot fumes that shroud Inherent Vice, there is a groovy slice of California noir spluttering to be seen and heard.

Patient audiences, who indulge the whims of writer-director Paul Thomas Anderson will be rewarded with a hallucinogenic crime caper crammed with quirky characters including another eye-catching lead performance from Joaquin Phoenix.

However, Anderson doesn't make it easy to fall in love with his picture.

Pacing is deliberately pedestrian and the running time, one puff shy of two-and-a-half hours, is a test of mental and physical endurance.

His script, adapted from Thomas Pynchon's novel of the same name, demands constant attention.

Very little happens over the course of the 149 minutes but Anderson presents the narrative as an almighty tangle of convoluted plots threads.

Take a toilet break at your peril.

Larry "Doc" Sportello (Phoenix) is a private eye and hippie, who lives in a ramshackle house on Gordita Beach and occasionally drifts into an office he rents, replete with sassy secretary (Maya Rudolph).

Alluring old flame Shasta Fay Hepworth (Katherine Waterston) returns unexpectedly to beg Doc's help tracking down her new beau, billionaire land developer Michael Z Wolfman (Eric Roberts).

"She was laying some heavy combination of face ingredients on Doc that he couldn't read," explains the rambling voiceover that accompanies this drug-fuelled lunacy.

Shasta claims Wolfman has been kidnapped and consigned to a mental institution by his money-grabbing wife (Serena Scott Thomas).

Doc takes on the case and also agrees two further assignments: to help Hope Harlingen (Jena Malone) track down her missing saxophonist husband (Owen Wilson), and reunite Black Guerrilla Family member Tariq Kahlil (Michael K Williams) with a wayward bodyguard (Christopher Allen Nelson), who owes him money.

The trails lead to a massage parlour where Jade (Hong Chau) tells Doc to "beware of the Golden Fang".

Intrigue piles upon deception and Doc seeks guidance from sexy Deputy District Attorney Penny Kimball (Reese Witherspoon) and bullying local cop, Lieutenant Detective Christian F "Bigfoot" Bjornsen (Josh Brolin).

Inherent Vice is the first film adaptation of Pynchon's kaleidoscopic oeuvre and it's easy to see why filmmakers have steered well clear.

Anderson does an admirable job conveying the freewheeling attitudes and paranoia of the era without tying himself completely in narrative knots.

Phoenix seems to be having a blast throughout and colourful supporting turns, including Martin Short as a drug-snorting dentist with wandering hands, churns the underlying black comedy.

That menagerie of dopers, musicians, hustlers, white supremacists and surfers is bewildering and Anderson regularly introduces new characters to keep our brains as scrambled as his bewildered hero.

Inherent Vice is a trip - whether the multiplex masses will want to embark on this journey into the criminal underbelly of neon-lit 1970s L.A. is open to debate.