DALLAS (Reuters) - Four hundred Super Bowl fans, who paid at least $900 per ticket, were denied their spots at the NFL's showcase game Sunday after an embarrassing mess-up over seating at the $1.2 billion Cowboys Stadium.

Another 850 fans with tickets in the affected section were relocated to other areas, the NFL said in a statement.

"Incomplete installation of temporary seats in a limited number of sections made the seats unusable," the NFL said in a statement.

The 400 fans were offered the chance to watch the game from a standing room only area or on monitors in a club area behind the Pittsburgh Steelers bench.

All the affected fans will receive a refund triple the cost of the face value of their tickets.

"We regret the situation and inconvenience that it may have caused. We will conduct a full review of this matter," said the NFL statement issued shortly before kickoff.

As well as the fall-out from the seating blunder, stadium officials had to deal with irate fans frustrated at the difficulty of moving between levels by elevator in the 100,000-seat venue.

(Reporting by Simon Evans in Dallas; Editing by Steve Ginsburg)