The result, a fair one in a game of few chances, extends City's unbeaten run to eight in all competitions and leaves their south-coast opponents without a win in nine.
Marlon King went closest for the home side when his right-footed effort flew just wide in the opening stages, while Craig Mackail-Smith fired narrowly off target in the second half for a Seagulls side who improved after the break.
That was about as good as it got in a game which registered 14 wayward attempts and just three on target, with visiting goalkeeper Steve Harper not forced into a single save.
Stalemate was hardly a surprise with Birmingham having not conceded in 325 league minutes going into the clash at St Andrew's, where they are unbeaten, while having to cope with the demands of four games in 10 days due to their Europa League exertions.
Blues boss Chris Hughton made just the one change from Wednesday's 1-0 victory over Leeds, on-loan top scorer Chris Wood - who claimed a League One winners' medal having spent the second half of last season with Brighton - coming in for matchwinner Nikola Zigic.
Hughton was an integral member of the coaching staff at Tottenham during Gus Poyet's time as a player at White Hart Lane, the Uruguayan admitting he learnt plenty under his stewardship as he establishes a career of his own in the dugout.
Poyet's tactics this afternoon were, however, hampered by the loss of Will Buckley in the pre-match warm-up, with five-goal Ashley Barnes regaining his place in the visitors' XI having initially been dropped.
Romain Vincelot and Inigo Calderon also came in for Gary Dicker and Lewis Dunk.
It was Birmingham who dominated the opening quarter, pressing Brighton at every opportunity while sending a handful of half-chances off target.
The best of those fell to King after nine minutes but he could only watch as his low strike from eight yards fell agonisingly wide with Harper helpless.
But that was the best opening of a disappointing and cagey first half. Wood headed well wide for the hosts from Chris Burke's 40th-minute cross, while the visitors posed next to no threat in the final third.
The second half started in much the same vein although the Seagulls were starting to pose more of a greater threat, Liam Bridcutt forcing Boaz Myhill into his first meaningful save of the afternoon.
Burke found the side-netting for Birmingham at the other end as the pace of the encounter picked up, with Brighton much livelier after the break.
Hughton changed his strikeforce after 67 minutes, introducing Zigic and Adam Rooney, while Brighton counterpart Poyet handed Billy Paynter a debut from the bench following his loan move from Leeds.
Mackail-Smith sent an effort narrowly wide from the edge of the penalty area before Gordon Greer's header brought a save from Myhill.
Zigic should have done better which a headed chance which fell his way, while Jean Beausejour fired a well-placed free-kick over in the 85th minute.
Brighton failed to settle matters with an even later set-piece as the game finished goalless.