The cost of special effects, not Hollywood stars, is responsible for increasing movie budgets, according to a report by the Wall Street Journal.

Escalating special effects costs have taken the budget of Sony's Spider-Man 3 to between $250 and $300 million, the publication has revealed.

Special effects have also resulted in the budgets of the next X-Men, Pirates of the Caribbean and Superman Returns exceeding $200 million.

"Effects, not stars, sell big movies these days," the newspaper said.