Russell Crowe and Ridley Scott are caught up in a new tiff on the set of their film Robin Hood, according to reports.

"The producers had to fly to London because Russell and Ridley won't talk to each other," an insider told the New York Post.

"Every time they stop filming, it costs the production millions of dollars."

The $175 million movie, which was originally titled 'Nottingham' but is now just 'Untitled Robin Hood Project.'

Last December, it was reported that Crowe no longer wanted to work with Scott, whom he blamed for their disastrous fourth collaboration, 'Body of Lies'. Then, in January, the actor reportedly ordered producers to get a new director and demanded script rewrites that devoted more of the plot to him.

The delays caused Sienna Miller to drop out, and Crowe had to go on a crash diet to drop 15 kg because, as one producer noted, "We can't have Robin Hood looking more like Friar Tuck."

Crowe's publicist, Alan Nierob, denied that there's any friction between star and director, insisting, "It's a good scene down there. Everything is on schedule."

Universal chairman Marc Shmuger said: "Ridley and Russell asked us to visit . . . to see more than an hour of footage they've already shot, which was nothing short of spectacular . . . We couldn't be more excited by what we saw. Russell and Ridley are working on their fifth film together and have one of the strongest and most collaborative working relationships.

"When it's news that a studio chairman and a film's producer (Brian Grazer) visit a production, it must be a very slow gossip day."