A writer is piling on the financial misery for divorce-bound Mel Gibson after telling a judge the star fiddled figures for a film to avoid paying him a fair fee.

Benedict Fitzgerald, who wrote Gibson’s controversial box office smash The Passion of the Christ, is suing him as he tries to get a larger paycheque for his work.

The writer said he accepted a low fee after being told the movie would have a reasonably modest $4-$7m production budget – but believes he has been lied to.

During the case, Gibson’s team produced accounting records putting the expenditure at $30m.

But Fitzgerald is now claiming the amount is even higher and is asking a judge to force a more thorough accounting.

He wants what he considers to be a fair writer’s fee based on the true cost of the movie, reported TMZ.com.

The news came just days after it emerged Gibson’s wife Robyn had filed for divorce – which could lead to a record settlement.

A large slice of Gibson’s estimated $950m fortune has come from The Passion of the Christ, which reportedly made over $600m around the world in cinemas alone.