Bill Murray has said he turned down the chance to star in a third Ghostbusters film because the screenplay was not up to scratch.

Appearing on the David Letterman show in the US on 7 June, the star of 1984's Ghostbusters and its poorly received 1989 sequel said he wanted any new instalment to be as funny as the film which launched the series.

"That's about all they [wanted] to know at Cannes, too," said Murray, who was promoting Wes Anderson's new film Moonrise Kingdom, which competed for this year's Palme d'Or at the French film festival. "They just don't have a really good script," he added. "It's hard. You know, even the second Ghostbusters wasn't as much fun for me as the first one. It's hard to make a sequel. That first one was so darn funny. It's hard for me."

However Murray hinted that writers may try to revamp the screenplay by Gene Stupnitsky and Lee Eisenberg of the US version of The Office, which has already been revised once by Ghostbusters star Dan Aykroyd. "I always drag my feet on it, but you know, we'll try again," he said.

Ghostbusters 3 was at one point expected to shoot last May, with Murray himself appearing in character as Peter Venkman at the 2010 Scream awards, suggesting he had warmed to the idea. Harold Ramis, who played Egon Spengler in the 80s films, was set to direct and co-star, with Aykroyd reprising his role as Ray Stantz. The latter described Murray's proposed return as the "comic role of a lifetime" and confirmed that the new film would see the team handing over ghostbusting duties to a new generation.

In August last year, Aykroyd appeared on the Dennis Miller show and appeared to hint that the film might go ahead without Murray. However, in February he said he was unsure if a third film would ever now be made, since his former co-star was not interested.