James Gandolfini plays mafia boss Tony Soprano

Bosses at television network HBO told cast members that work on the fifth series has been postponed indefinitely, according to Thursday editions of the Daily News and the New York Post.

The last offer made to Gandolfini for the 13-episode fifth season was for $11m (�6.8m), part of which was to be paid in profit participation.

But Gandolfini was reported to be asking for as much as $27m (�16.8m), and $16.7m (�10.4m) for a sixth season, should one be ordered.

It should be beneath HBO to treat one of their biggest stars, moneymakers and friends like this Dan Klore, James Gandolfini's spokesman

The network says it was backed into a corner by a lawsuit Gandolfini filed in a California court last week, claiming his contract for the fifth season is invalid.

HBO has, meanwhile, filed a countersuit to ensure Gandolfini turned up on the first day of shooting.

Water pistol

"Gandolfini's agents believe they are holding a gun to HBO's head to get them to pay this massive salary increase," said HBO's lawyer, Bert Fields.

"But it's really a water pistol - and it doesn't even have any water in it."

HBO said it had accommodated Gandolfini's schedule when he wanted to do movies, and that it was tolerant of the personal problems he had experienced while starring in the show.

"Let HBO say whatever they want to say," said Gandolfini's spokesman, Dan Klores.

"It should be beneath them to treat one of their biggest stars, moneymakers and friends like this."

If the cable network was forced to cancel The Sopranos it would be forfeiting its highest-rated flagship show a year early and losing millions of viewers.