Zachary Quinto (left) plays Spock in the film by JJ Abrams (right)

Paramount Pictures said the movie would still be finished on schedule but wanted it to open in the summer.

"Summer is where you see the Star Wars and the Transformers," said studio spokesman Michael Vollman. "Star Trek is in that league."

The film is being directed by Lost creator JJ Abrams and stars Chris Pine as Kirk and Zachary Quinto as Spock.

British comedian Simon Pegg is also due to step into James Doohan's shoes by playing the Starship Enterprise's chief engineer, Scotty.

The movie, which has not yet been named, was originally going to be released on Boxing Day.

Strong competition

Paramount insisted the decision was a vote of confidence in the production and was not related to the recent Hollywood writers' strike.

"Star Trek is in fantastic shape. This is all about box-office potential," said Mr Vollman.

The film had been in production without its screenwriters available to make revisions.

The studio is aiming to release Star Trek on 8 May 2009, putting it in the middle of some strong competition.

X-Men Origins: Wolverine, starring Hugh Jackman, is scheduled to open a week earlier.