Nicolas Chartier, who admitted urging Academy members not to vote for James Cameron's Avatar, has had his invitation to the prize-giving withdrawn

A producer on Oscar frontrunner The Hurt Locker has been banned from Sunday night's awards ceremony for campaigning openly against a rival film. Nicolas Chartier, who financed the $15m Iraq war drama himself, sent emails urging Academy voters to vote for his movie and "not a $500m film", a clear reference to James Cameron's Avatar, which is also in the running for the best picture prize.

The Academy of Motion Pictures, Arts and Sciences said yesterday that Chartier was censured by the executive committee of its producers' branch during a special session on Monday for "an ethical lapse". Academy rules prohibit "casting a negative or derogatory light on a competing film". For his pains, Chartier will be barred from the Kodak Theatre in Los Angeles this weekend, although he will receive a statuette later if The Hurt Locker takes the gong.

The move is being seen as a high-profile effort to police overzealous awards campaigning, though critics have suggested that the practice is widespread and Chartier's punishment unfair.

Meanwhile, members of The Hurt Locker's creative team have reportedly moved to distance themselves from Chartier. Screenwriter Mark Boal, also one of the project's three other named producers, told the Daily Beast that the Frenchman was something of a "reactive" personality prone to fits of anger.

"It was a hard movie to get made," Boal said. "It was a challenging shoot, and it's the nature of those things that tempers can flare and strong disagreements can arise. And Nic was eventually asked not to come back to the set."

He added: "Everyone understands that Nic bears the responsibility for his mistake 100% on his own shoulders."

Critics of the Academy's decision include Scott Feinberg of industry blog And The Winner Is, who tweeted: "The banning of THE HURT LOCKER producer from the Oscars is bullshit. If you're gonna ban him, you should ban 20 others too. RT if you agree."

The Hurt Locker is currently tied with Avatar on nine Oscar nominations. Other films vying for the best picture prize include Quentin Tarantino's Inglourious Basterds, the Coen brothers' A Serious Man and the Oprah Winfrey-backed Precious.