FANS have gone into a "frenzy" trying to buy advance tickets for the final Batman film The Dark Knight Rises, crashing the Sydney and Melbourne IMAX websites.

Thousands of people per minute visited the IMAX Theatre Sydney website when tickets went on sale at 1pm.

IMAX Theatre Sydney CEO Mark Bretherton said the ticketing software "crashed" for 20 minutes as fans tried to purchase tickets for the film, which opens in cinemas on Thursday, July 19.

"It was a frenzy," he said.

"You have the die hards who have to see it first, the crazy ones where nothing but the midnight sessions will do.

"There are some serious fans out there."

Mr Bretherton said the issue was with people trying to open multiple browsers to buy tickets, which was the same problem that caused the IMAX Melbourne website to crash when tickets went on sale at 9am this morning.

Frustrated fans took to the IMAX Sydney Facebook page to voice their outrage.

," posted Jake Small.

Tom Dixon: "Had my seats picked and details in correctly, got told there was a problem and to try again. Tried again: This session is sold out. So f***ing mad."

The Dark Knight Rises features an extra hour of footage only available in IMAX.

Mr Bretherton compared the demand to that experienced with the Harry Potter franchise and said they may put on extra sessions, including at 3.30am.

"It's possible to open it up to more sessions but we're limited because we are a single screen and there only 24 hours in one day," he said.

Event Cinemas and Hoyts also had an overwhelming response from Batman fans, with several sessions selling out back-to-back and only a handful of seats remaining for midnight screenings.

The Dark Knight Rises is the final film in director Christopher Nolan's Batman trilogy and sees Christian Bale returning to the role of the caped crusader.