Peter Jackson's film adaptation of The Hobbit will be split into three films, the director and the studios behind the venture said on Monday.

Jackson said that given the richness of the story – which is set 60 years before The Lord of the Rings – he decided after wrapping up shooting recently in New Zealand that what was originally planned as two films would now be a trilogy.

"I'm delighted that New Line, MGM and Warner Bros are equally enthusiastic about bringing fans this expansive tale across three films," Jackson said in a statement.

"It has been an unexpected journey indeed, and in the words of Professor Tolkien himself, 'a tale that grew in the telling'," Jackson said in a statement on his Facebook site.

The Hobbit, written by JRR Tolkien, is the prequel to the British author's epic fantasy The Lord of the Rings, which Jackson made into three Oscar-winning films about 10 years ago.

A spokesman for New Line said the third Hobbit film would be released in the summer of 2014. The first two Hobbit movies, starring British actor Martin Freeman as Bilbo Baggins, have already been announced for release in December 2012 and December 2013.

"It is only at the end of a shoot that you finally get the chance to sit down and have a look at the film you have made," Jackson said on his Facebook page.

"We know how much of the story of Bilbo Baggins, the Wizard Gandalf, the Dwarves of Erebor, the rise of the Necromancer, and the Battle of Dol Guldur will remain untold if we do not take this chance," he added.

The Lord of the Rings consisted of three parts totalling 1,008 pages which lent itself to adaptation into three separate films. However, The Hobbit is only 310 pages along which suggests it will require rewriting and the addition of new scenes and characters to stretch it over three films.